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Posted to commits@tajo.apache.org by hy...@apache.org on 2015/09/07 09:03:02 UTC

[2/5] tajo git commit: TAJO-1818: Separate sql parser into an independent maven module.

http://git-wip-us.apache.org/repos/asf/tajo/blob/33b8893f/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLAnalyzer.java
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diff --git a/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLAnalyzer.java b/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLAnalyzer.java
new file mode 100644
index 0000000..b9b86ac
--- /dev/null
+++ b/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLAnalyzer.java
@@ -0,0 +1,1986 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.parser.sql;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
+import org.antlr.v4.runtime.ANTLRInputStream;
+import org.antlr.v4.runtime.CommonTokenStream;
+import org.antlr.v4.runtime.misc.NotNull;
+import org.antlr.v4.runtime.tree.TerminalNode;
+import org.apache.tajo.SessionVars;
+import org.apache.tajo.algebra.*;
+import org.apache.tajo.algebra.Aggregation.GroupType;
+import org.apache.tajo.algebra.CreateIndex.IndexMethodSpec;
+import org.apache.tajo.algebra.DataTypeExpr.MapType;
+import org.apache.tajo.algebra.LiteralValue.LiteralType;
+import org.apache.tajo.algebra.Sort.SortSpec;
+import org.apache.tajo.exception.SQLSyntaxError;
+import org.apache.tajo.exception.TajoRuntimeException;
+import org.apache.tajo.parser.sql.SQLParser.*;
+import org.apache.tajo.storage.StorageConstants;
+import org.apache.tajo.util.StringUtils;
+
+import java.util.*;
+
+import static org.apache.tajo.algebra.Aggregation.GroupElement;
+import static org.apache.tajo.algebra.CreateTable.*;
+import static org.apache.tajo.algebra.WindowSpec.WindowFrameEndBoundType;
+import static org.apache.tajo.algebra.WindowSpec.WindowFrameStartBoundType;
+import static org.apache.tajo.common.TajoDataTypes.Type;
+import static org.apache.tajo.parser.sql.SQLParser.*;
+
+public class SQLAnalyzer extends SQLParserBaseVisitor<Expr> {
+
+  public Expr parse(String sql) throws SQLSyntaxError {
+    ANTLRInputStream input = new ANTLRInputStream(sql);
+    SQLLexer lexer = new SQLLexer(input);
+    CommonTokenStream tokens = new CommonTokenStream(lexer);
+    SqlContext context;
+    try {
+      SQLParser parser = new SQLParser(tokens);
+      parser.setBuildParseTree(true);
+      parser.removeErrorListeners();
+
+      parser.setErrorHandler(new SQLErrorStrategy());
+      parser.addErrorListener(new SQLErrorListener());
+      context = parser.sql();
+    } catch (SQLParseError e) {
+      throw new SQLSyntaxError(e.getMessage());
+    }
+    return visitSql(context);
+  }
+
+  private static boolean checkIfExist(Object obj) {
+    return obj != null;
+  }
+
+  @Override
+  public Expr visitSql(SqlContext ctx) {
+    Expr statement = visit(ctx.statement());
+    if (checkIfExist(ctx.explain_clause())) {
+      return new Explain(statement, checkIfExist(ctx.explain_clause().GLOBAL()));
+    } else {
+      return statement;
+    }
+  }
+
+  public Expr visitSession_statement(@NotNull Session_statementContext ctx) {
+
+    if (checkIfExist(ctx.CATALOG())) {
+
+      return new SetSession(SessionVars.CURRENT_DATABASE.name(), ctx.dbname.getText());
+
+
+    } else if (checkIfExist(ctx.name)) {
+      String value;
+      if (checkIfExist(ctx.boolean_literal())) {
+        value = ctx.boolean_literal().getText();
+      } else if (checkIfExist(ctx.Character_String_Literal())) {
+        value = stripQuote(ctx.Character_String_Literal().getText());
+      } else if (checkIfExist(ctx.signed_numerical_literal())) {
+        value = ctx.signed_numerical_literal().getText();
+      } else {
+        value = null;
+      }
+      return new SetSession(ctx.name.getText(), value);
+
+
+    } else if (checkIfExist(ctx.TIME()) && checkIfExist(ctx.ZONE())) {
+
+      String value;
+      if (checkIfExist(ctx.Character_String_Literal())) {
+        value = stripQuote(ctx.Character_String_Literal().getText());
+      } else if (checkIfExist(ctx.signed_numerical_literal())) {
+        value = ctx.signed_numerical_literal().getText();
+      } else {
+        value = null;
+      }
+      return new SetSession(SessionVars.TIMEZONE.name(), value);
+
+    } else {
+      throw new TajoRuntimeException(new SQLSyntaxError("Unsupported session statement"));
+    }
+  }
+
+  @Override
+  public Expr visitNon_join_query_expression(Non_join_query_expressionContext ctx) {
+
+    Expr current = visitNon_join_query_term(ctx.non_join_query_term());
+    if (ctx.getChildCount() == 1) {
+      return current;
+    }
+
+    OpType operatorType;
+    Expr left;
+    for (int i = 1; i < ctx.getChildCount(); i++) {
+      int idx = i;
+      boolean distinct = true;
+
+      if (ctx.getChild(idx) instanceof TerminalNode) {
+        if (((TerminalNode) ctx.getChild(idx)).getSymbol().getType() == UNION) {
+          operatorType = OpType.Union;
+        } else {
+          operatorType = OpType.Except;
+        }
+
+        idx++;
+
+        if (ctx.getChild(idx) instanceof TerminalNode) {
+          if (((TerminalNode) ctx.getChild(idx)).getSymbol().getType() == ALL) {
+            distinct = false;
+          }
+
+          idx++;
+        }
+
+        Query_termContext queryTermContext =
+            (Query_termContext) ctx.getChild(idx);
+        Expr right = visitQuery_term(queryTermContext);
+
+        left = current;
+        current = new SetOperation(operatorType, left, right, distinct);
+
+        i = idx;
+      }
+    }
+
+    return current;
+  }
+
+  @Override
+  public Expr visitNon_join_query_term(Non_join_query_termContext ctx) {
+
+    Expr current = visitNon_join_query_primary(ctx.non_join_query_primary());
+    Expr left;
+
+    for (int i = 1; i < ctx.getChildCount(); ) {
+      int idx = i;
+      boolean distinct = true;
+
+      if (ctx.getChild(idx) instanceof TerminalNode) {
+        if (((TerminalNode) ctx.getChild(idx)).getSymbol().getType() == INTERSECT) {
+          idx++;
+        }
+
+        if (ctx.getChild(idx) instanceof TerminalNode) {
+          if (((TerminalNode) ctx.getChild(idx)).getSymbol().getType() == ALL) {
+            distinct = false;
+            idx++;
+          }
+        }
+
+        Query_primaryContext queryPrimaryContext = (Query_primaryContext) ctx.getChild(idx);
+        Expr right = visitQuery_primary(queryPrimaryContext);
+
+        left = current;
+        current = new SetOperation(OpType.Intersect, left, right, distinct);
+
+        i += idx;
+      }
+    }
+
+    return current;
+
+  }
+
+  @Override
+  public Expr visitNon_join_query_primary(Non_join_query_primaryContext ctx) {
+    if (ctx.simple_table() != null) {
+      return visitSimple_table(ctx.simple_table());
+    } else if (ctx.non_join_query_expression() != null) {
+      return visitNon_join_query_expression(ctx.non_join_query_expression());
+    }
+    return visitChildren(ctx);
+  }
+
+  @Override
+  public Expr visitQuery_specification(Query_specificationContext ctx) {
+    Expr current = null;
+    if (ctx.table_expression() != null) {
+      current = visitFrom_clause(ctx.table_expression().from_clause());
+
+      if (ctx.table_expression().where_clause() != null) {
+        Selection selection = visitWhere_clause(ctx.table_expression().where_clause());
+        selection.setChild(current);
+        current = selection;
+      }
+
+      if (ctx.table_expression().groupby_clause() != null) {
+        Aggregation aggregation = visitGroupby_clause(ctx.table_expression().groupby_clause());
+        aggregation.setChild(current);
+        current = aggregation;
+
+        if (ctx.table_expression().having_clause() != null) {
+          Expr havingCondition = visitBoolean_value_expression(
+              ctx.table_expression().having_clause().boolean_value_expression());
+          Having having = new Having(havingCondition);
+          having.setChild(current);
+          current = having;
+        }
+      }
+
+      if (ctx.table_expression().orderby_clause() != null) {
+        Sort sort = visitOrderby_clause(ctx.table_expression().orderby_clause());
+        sort.setChild(current);
+        current = sort;
+      }
+
+      if (checkIfExist(ctx.table_expression().window_clause())) {
+        Window window = visitWindow_clause(ctx.table_expression().window_clause());
+        window.setChild(current);
+        current = window;
+      }
+
+      if (ctx.table_expression().limit_clause() != null) {
+        Limit limit = visitLimit_clause(ctx.table_expression().limit_clause());
+        limit.setChild(current);
+        current = limit;
+      }
+    }
+
+    Projection projection = visitSelect_list(ctx.select_list());
+
+    if (ctx.set_qualifier() != null && ctx.set_qualifier().DISTINCT() != null) {
+      projection.setDistinct();
+    }
+
+    if (current != null) {
+      projection.setChild(current);
+    }
+
+    current = projection;
+
+    return current;
+  }
+
+  /**
+   * <pre>
+   *   select_list
+   *   : select_sublist (COMMA select_sublist)*
+   *   ;
+   * </pre>
+   *
+   * @param ctx
+   * @return
+   */
+  @Override
+  public Projection visitSelect_list(Select_listContext ctx) {
+    Projection projection = new Projection();
+    NamedExpr[] targets = new NamedExpr[ctx.select_sublist().size()];
+    for (int i = 0; i < targets.length; i++) {
+      targets[i] = visitSelect_sublist(ctx.select_sublist(i));
+    }
+    projection.setNamedExprs(targets);
+
+    return projection;
+  }
+
+  /**
+   * <pre>
+   *   select_sublist
+   *   : derived_column
+   *   | asterisked_qualifier
+   *   ;
+   * </pre>
+   *
+   * @param ctx
+   * @return
+   */
+  @Override
+  public NamedExpr visitSelect_sublist(Select_sublistContext ctx) {
+    if (ctx.qualified_asterisk() != null) {
+      return visitQualified_asterisk(ctx.qualified_asterisk());
+    } else {
+      return visitDerived_column(ctx.derived_column());
+    }
+  }
+
+  @Override
+  public RelationList visitFrom_clause(From_clauseContext ctx) {
+    Expr[] relations = new Expr[ctx.table_reference_list().table_reference().size()];
+    for (int i = 0; i < relations.length; i++) {
+      relations[i] = visitTable_reference(ctx.table_reference_list().table_reference(i));
+    }
+    return new RelationList(relations);
+  }
+
+  @Override
+  public Selection visitWhere_clause(Where_clauseContext ctx) {
+    return new Selection(visitSearch_condition(ctx.search_condition()));
+  }
+
+  @Override
+  public Aggregation visitGroupby_clause(Groupby_clauseContext ctx) {
+    Aggregation clause = new Aggregation();
+
+    // If grouping group is not empty
+    if (ctx.grouping_element_list().grouping_element().get(0).empty_grouping_set() == null) {
+      int elementSize = ctx.grouping_element_list().grouping_element().size();
+      ArrayList<GroupElement> groups = new ArrayList<GroupElement>(elementSize + 1);
+      ArrayList<Expr> ordinaryExprs = null;
+      int groupSize = 1;
+      groups.add(null);
+
+      for (int i = 0; i < elementSize; i++) {
+        Grouping_elementContext element =
+            ctx.grouping_element_list().grouping_element().get(i);
+        if (element.ordinary_grouping_set() != null) {
+          if (ordinaryExprs == null) {
+            ordinaryExprs = new ArrayList<Expr>();
+          }
+          Collections.addAll(ordinaryExprs, getRowValuePredicandsFromOrdinaryGroupingSet(element.ordinary_grouping_set()));
+        } else if (element.rollup_list() != null) {
+          groupSize++;
+          groups.add(new GroupElement(GroupType.Rollup,
+              getRowValuePredicandsFromOrdinaryGroupingSetList(element.rollup_list().c)));
+        } else if (element.cube_list() != null) {
+          groupSize++;
+          groups.add(new GroupElement(GroupType.Cube,
+              getRowValuePredicandsFromOrdinaryGroupingSetList(element.cube_list().c)));
+        }
+      }
+
+      if (ordinaryExprs != null) {
+        groups.set(0, new GroupElement(GroupType.OrdinaryGroup, ordinaryExprs.toArray(new Expr[ordinaryExprs.size()])));
+        clause.setGroups(groups.subList(0, groupSize).toArray(new GroupElement[groupSize]));
+      } else if (groupSize > 1) {
+        clause.setGroups(groups.subList(1, groupSize).toArray(new GroupElement[groupSize - 1]));
+      }
+    }
+
+    return clause;
+  }
+
+  @Override public WindowFunctionExpr visitWindow_function(@NotNull Window_functionContext context) {
+    WindowFunctionExpr windowFunction = null;
+
+    Window_function_typeContext functionType = context.window_function_type();
+    GeneralSetFunctionExpr functionBody;
+    if (checkIfExist(functionType.rank_function_type())) {
+      Rank_function_typeContext rankFunction = functionType.rank_function_type();
+      if (checkIfExist(rankFunction.RANK())) {
+        functionBody = new GeneralSetFunctionExpr("rank", false, new Expr[] {});
+      } else if (checkIfExist(rankFunction.DENSE_RANK())) {
+        functionBody = new GeneralSetFunctionExpr("dense_rank", false, new Expr[] {});
+      } else if (checkIfExist(rankFunction.PERCENT_RANK())) {
+        functionBody = new GeneralSetFunctionExpr("percent_rank", false, new Expr[] {});
+      } else {
+        functionBody = new GeneralSetFunctionExpr("cume_dist", false, new Expr[] {});
+      }
+    } else if (checkIfExist(functionType.ROW_NUMBER())) {
+      functionBody = new GeneralSetFunctionExpr("row_number", false, new Expr[] {});
+    } else if (checkIfExist(functionType.FIRST_VALUE())) {
+      functionBody = new GeneralSetFunctionExpr("first_value", false, new Expr[]{ visitColumn_reference(functionType.column_reference())});
+    } else if (checkIfExist(functionType.LAST_VALUE())) {
+      functionBody = new GeneralSetFunctionExpr("last_value", false, new Expr[]{visitColumn_reference(functionType.column_reference())});
+    } else if (checkIfExist(functionType.LAG())) {
+      if (checkIfExist(functionType.numeric_value_expression())) {
+        if (checkIfExist(functionType.common_value_expression())) {
+          functionBody = new GeneralSetFunctionExpr("lag", false, new Expr[]{visitColumn_reference(functionType.column_reference()),
+              visitNumeric_value_expression(functionType.numeric_value_expression()),
+              visitCommon_value_expression(functionType.common_value_expression())});
+        } else {
+          functionBody = new GeneralSetFunctionExpr("lag", false, new Expr[]{visitColumn_reference(functionType.column_reference()),
+              visitNumeric_value_expression(functionType.numeric_value_expression())});
+        }
+      } else {
+        functionBody = new GeneralSetFunctionExpr("lag", false, new Expr[]{visitColumn_reference(functionType.column_reference())});
+      }
+    } else if (checkIfExist(functionType.LEAD())) {
+      if (checkIfExist(functionType.numeric_value_expression())) {
+        if (checkIfExist(functionType.common_value_expression())) {
+          functionBody = new GeneralSetFunctionExpr("lead", false, new Expr[]{visitColumn_reference(functionType.column_reference()),
+              visitNumeric_value_expression(functionType.numeric_value_expression()),
+              visitCommon_value_expression(functionType.common_value_expression())});
+        } else {
+          functionBody = new GeneralSetFunctionExpr("lead", false, new Expr[]{visitColumn_reference(functionType.column_reference()),
+              visitNumeric_value_expression(functionType.numeric_value_expression())});
+        }
+      } else {
+        functionBody = new GeneralSetFunctionExpr("lead", false, new Expr[]{visitColumn_reference(functionType.column_reference())});
+      }
+    } else {
+      functionBody = visitAggregate_function(functionType.aggregate_function());
+    }
+    windowFunction = new WindowFunctionExpr(functionBody);
+
+    Window_name_or_specificationContext windowNameOrSpec = context.window_name_or_specification();
+    if (checkIfExist(windowNameOrSpec.window_name())) {
+      windowFunction.setWindowName(windowNameOrSpec.window_name().getText());
+    } else {
+      windowFunction.setWindowSpec(buildWindowSpec(windowNameOrSpec.window_specification()));
+    }
+
+    return windowFunction;
+  }
+
+  @Override
+  public Window visitWindow_clause(@NotNull Window_clauseContext ctx) {
+    Window.WindowDefinition [] definitions =
+        new Window.WindowDefinition[ctx.window_definition_list().window_definition().size()];
+    for (int i = 0; i < definitions.length; i++) {
+      Window_definitionContext windowDefinitionContext = ctx.window_definition_list().window_definition(i);
+      String windowName = windowDefinitionContext.window_name().identifier().getText();
+      WindowSpec windowSpec = buildWindowSpec(windowDefinitionContext.window_specification());
+      definitions[i] = new Window.WindowDefinition(windowName, windowSpec);
+    }
+    return new Window(definitions);
+  }
+
+  public WindowSpec buildWindowSpec(Window_specificationContext ctx) {
+    WindowSpec windowSpec = new WindowSpec();
+    if (checkIfExist(ctx.window_specification_details())) {
+      Window_specification_detailsContext windowSpecDetail = ctx.window_specification_details();
+
+      if (checkIfExist(windowSpecDetail.existing_window_name())) {
+        windowSpec.setWindowName(windowSpecDetail.existing_window_name().getText());
+      }
+
+      if (checkIfExist(windowSpecDetail.window_partition_clause())) {
+        windowSpec.setPartitionKeys(
+            buildRowValuePredicands(windowSpecDetail.window_partition_clause().row_value_predicand_list()));
+      }
+
+      if (checkIfExist(windowSpecDetail.window_order_clause())) {
+        windowSpec.setSortSpecs(
+            buildSortSpecs(windowSpecDetail.window_order_clause().orderby_clause().sort_specifier_list()));
+      }
+
+      if (checkIfExist(windowSpecDetail.window_frame_clause())) {
+        Window_frame_clauseContext frameContext = windowSpecDetail.window_frame_clause();
+
+        WindowSpec.WindowFrameUnit unit;
+        // frame unit - there are only two cases: RANGE and ROW
+        if (checkIfExist(frameContext.window_frame_units().RANGE())) {
+          unit = WindowSpec.WindowFrameUnit.RANGE;
+        } else {
+          unit = WindowSpec.WindowFrameUnit.ROW;
+        }
+
+        WindowSpec.WindowFrame windowFrame;
+
+        if (checkIfExist(frameContext.window_frame_extent().window_frame_between())) { // when 'between' is given
+          Window_frame_betweenContext between = frameContext.window_frame_extent().window_frame_between();
+          WindowSpec.WindowStartBound startBound = buildWindowStartBound(between.window_frame_start_bound());
+          WindowSpec.WindowEndBound endBound = buildWindowEndBound(between.window_frame_end_bound());
+
+          windowFrame = new WindowSpec.WindowFrame(unit, startBound, endBound);
+        } else { // if there is only start bound
+          WindowSpec.WindowStartBound startBound =
+              buildWindowStartBound(frameContext.window_frame_extent().window_frame_start_bound());
+          windowFrame = new WindowSpec.WindowFrame(unit, startBound);
+        }
+
+        windowSpec.setWindowFrame(windowFrame);
+      }
+    }
+    return windowSpec;
+  }
+
+  public WindowSpec.WindowStartBound buildWindowStartBound(Window_frame_start_boundContext context) {
+    WindowFrameStartBoundType boundType = null;
+    if (checkIfExist(context.UNBOUNDED())) {
+      boundType = WindowFrameStartBoundType.UNBOUNDED_PRECEDING;
+    } else if (checkIfExist(context.unsigned_value_specification())) {
+      boundType = WindowFrameStartBoundType.PRECEDING;
+    } else {
+      boundType = WindowFrameStartBoundType.CURRENT_ROW;
+    }
+
+    WindowSpec.WindowStartBound bound = new WindowSpec.WindowStartBound(boundType);
+    if (boundType == WindowFrameStartBoundType.PRECEDING) {
+      bound.setNumber(visitUnsigned_value_specification(context.unsigned_value_specification()));
+    }
+
+    return bound;
+  }
+
+  public WindowSpec.WindowEndBound buildWindowEndBound(Window_frame_end_boundContext context) {
+    WindowFrameEndBoundType boundType;
+    if (checkIfExist(context.UNBOUNDED())) {
+      boundType = WindowFrameEndBoundType.UNBOUNDED_FOLLOWING;
+    } else if (checkIfExist(context.unsigned_value_specification())) {
+      boundType = WindowFrameEndBoundType.FOLLOWING;
+    } else {
+      boundType = WindowFrameEndBoundType.CURRENT_ROW;
+    }
+
+    WindowSpec.WindowEndBound endBound = new WindowSpec.WindowEndBound(boundType);
+    if (boundType == WindowFrameEndBoundType.FOLLOWING) {
+      endBound.setNumber(visitUnsigned_value_specification(context.unsigned_value_specification()));
+    }
+
+    return endBound;
+  }
+
+  public Sort.SortSpec[] buildSortSpecs(Sort_specifier_listContext context) {
+    int size = context.sort_specifier().size();
+
+    Sort.SortSpec specs[] = new Sort.SortSpec[size];
+    for (int i = 0; i < size; i++) {
+      Sort_specifierContext specContext = context.sort_specifier(i);
+      Expr sortKeyExpr = visitRow_value_predicand(specContext.key);
+      specs[i] = new Sort.SortSpec(sortKeyExpr);
+      if (specContext.order_specification() != null) {
+        if (specContext.order.DESC() != null) {
+          specs[i].setDescending();
+        }
+      }
+
+      if (specContext.null_ordering() != null) {
+        if (specContext.null_ordering().FIRST() != null) {
+          specs[i].setNullFirst();
+        }
+      }
+    }
+
+    return specs;
+  }
+
+  @Override
+  public Sort visitOrderby_clause(Orderby_clauseContext ctx) {
+    return new Sort(buildSortSpecs(ctx.sort_specifier_list()));
+  }
+
+  @Override
+  public Limit visitLimit_clause(Limit_clauseContext ctx) {
+    return new Limit(visitNumeric_value_expression(ctx.numeric_value_expression()));
+  }
+
+  @Override
+  public Expr visitJoined_table(Joined_tableContext ctx) {
+    Expr top = visitTable_primary(ctx.table_primary());
+
+    // The following loop builds a left deep join tree.
+    Join join;
+    for (int i = 0; i < ctx.joined_table_primary().size(); i++) {
+      join = visitJoined_table_primary(ctx.joined_table_primary(i));
+      join.setLeft(top);
+      top = join;
+    }
+
+    return top;
+  }
+
+  @Override
+  public Join visitJoined_table_primary(Joined_table_primaryContext ctx) {
+    Join join;
+    if (ctx.CROSS() != null) {
+      join = new Join(JoinType.CROSS);
+    } else if (ctx.UNION() != null) {
+      join = new Join(JoinType.UNION);
+    } else { // qualified join or natural
+      if (ctx.join_type() != null && ctx.join_type().outer_join_type() != null) {
+        Outer_join_type_part2Context outer_join_typeContext = ctx.join_type().outer_join_type()
+            .outer_join_type_part2();
+        if (outer_join_typeContext.FULL() != null) {
+          join = new Join(JoinType.FULL_OUTER);
+        } else if (outer_join_typeContext.LEFT() != null) {
+          join = new Join(JoinType.LEFT_OUTER);
+        } else {
+          join = new Join(JoinType.RIGHT_OUTER);
+        }
+      } else {
+        join = new Join(JoinType.INNER);
+      }
+
+      if (ctx.NATURAL() != null) {
+        join.setNatural();
+      }
+
+      if (ctx.join_specification() != null) { // only for qualified join
+        if (ctx.join_specification().join_condition() != null) {
+          Expr searchCondition = visitSearch_condition(ctx.join_specification().
+              join_condition().search_condition());
+          join.setQual(searchCondition);
+        } else if (ctx.join_specification().named_columns_join() != null) {
+          ColumnReferenceExpr[] columns = buildColumnReferenceList(ctx.join_specification().
+              named_columns_join().column_reference_list());
+          join.setJoinColumns(columns);
+        }
+      }
+    }
+
+    join.setRight(visitTable_primary(ctx.right));
+    return join;
+  }
+
+  private Expr[] getRowValuePredicandsFromOrdinaryGroupingSetList(Ordinary_grouping_set_listContext ctx) {
+    ArrayList<Expr> rowValuePredicands = new ArrayList<Expr>();
+    for (int i = 0; i < ctx.ordinary_grouping_set().size(); i++) {
+      Collections.addAll(rowValuePredicands, getRowValuePredicandsFromOrdinaryGroupingSet(ctx.ordinary_grouping_set(i)));
+    }
+    return rowValuePredicands.toArray(new Expr[rowValuePredicands.size()]);
+  }
+
+  private Expr[] getRowValuePredicandsFromOrdinaryGroupingSet(Ordinary_grouping_setContext ctx) {
+    ArrayList<Expr> rowValuePredicands = new ArrayList<Expr>();
+    if (ctx.row_value_predicand() != null) {
+      rowValuePredicands.add(visitRow_value_predicand(ctx.row_value_predicand()));
+    }
+    if (ctx.row_value_predicand_list() != null) {
+      Collections.addAll(rowValuePredicands, buildRowValuePredicands(ctx.row_value_predicand_list()));
+    }
+    return rowValuePredicands.toArray(new Expr[rowValuePredicands.size()]);
+  }
+
+  private Expr[] buildRowValuePredicands(Row_value_predicand_listContext ctx) {
+    Expr[] rowValuePredicands = new Expr[ctx.row_value_predicand().size()];
+    for (int i = 0; i < rowValuePredicands.length; i++) {
+      rowValuePredicands[i] = visitRow_value_predicand(ctx.row_value_predicand(i));
+    }
+    return rowValuePredicands;
+  }
+
+  private ColumnReferenceExpr[] buildColumnReferenceList(Column_reference_listContext ctx) {
+    ColumnReferenceExpr[] columnRefs = new ColumnReferenceExpr[ctx.column_reference().size()];
+    for (int i = 0; i < columnRefs.length; i++) {
+      columnRefs[i] = visitColumn_reference(ctx.column_reference(i));
+    }
+    return columnRefs;
+  }
+
+  @Override
+  public Expr visitTable_primary(Table_primaryContext ctx) {
+    if (ctx.table_or_query_name() != null) {
+      Relation relation = new Relation(ctx.table_or_query_name().getText());
+      if (ctx.alias != null) {
+        relation.setAlias(ctx.alias.getText());
+      }
+      return relation;
+    } else if (ctx.derived_table() != null) {
+      return new TablePrimarySubQuery(ctx.name.getText(), visit(ctx.derived_table().table_subquery()));
+    } else {
+      return null;
+    }
+  }
+
+
+  @Override
+  public Expr visitSubquery(SubqueryContext ctx) {
+    return visitQuery_expression(ctx.query_expression());
+  }
+
+  @Override
+  public BetweenPredicate visitBetween_predicate(Between_predicateContext ctx) {
+    Expr predicand = visitRow_value_predicand(ctx.predicand);
+    Expr begin = visitRow_value_predicand(ctx.between_predicate_part_2().begin);
+    Expr end = visitRow_value_predicand(ctx.between_predicate_part_2().end);
+    return new BetweenPredicate(checkIfExist(ctx.between_predicate_part_2().NOT()),
+        checkIfExist(ctx.between_predicate_part_2().SYMMETRIC()), predicand, begin, end);
+  }
+
+  @Override
+  public CaseWhenPredicate visitSimple_case(Simple_caseContext ctx) {
+    Expr leftTerm = visitBoolean_value_expression(ctx.boolean_value_expression());
+    CaseWhenPredicate caseWhen = new CaseWhenPredicate();
+
+    for (int i = 0; i < ctx.simple_when_clause().size(); i++) {
+      Simple_when_clauseContext simpleWhenCtx = ctx.simple_when_clause(i);
+      BinaryOperator bin = new BinaryOperator(OpType.Equals, leftTerm,
+          visitValue_expression(simpleWhenCtx.search_condition().value_expression()));
+      caseWhen.addWhen(bin, buildCaseResult(simpleWhenCtx.result()));
+    }
+    if (ctx.else_clause() != null) {
+      caseWhen.setElseResult(buildCaseResult(ctx.else_clause().result()));
+    }
+    return caseWhen;
+  }
+
+  private Expr buildCaseResult(ResultContext result) {
+    if (result.NULL() != null) {
+      return new NullLiteral();
+    } else {
+      return visitValue_expression(result.value_expression());
+    }
+  }
+
+  @Override
+  public CaseWhenPredicate visitSearched_case(Searched_caseContext ctx) {
+    CaseWhenPredicate caseWhen = new CaseWhenPredicate();
+
+    for (int i = 0; i < ctx.searched_when_clause().size(); i++) {
+      Searched_when_clauseContext searchedWhenCtx = ctx.searched_when_clause(i);
+      caseWhen.addWhen(
+          visitSearch_condition(searchedWhenCtx.search_condition()),
+          buildCaseResult(searchedWhenCtx.result()));
+    }
+    if (ctx.else_clause() != null) {
+      caseWhen.setElseResult(buildCaseResult(ctx.else_clause().result()));
+    }
+    return caseWhen;
+  }
+
+  @Override
+  public Expr visitCommon_value_expression(Common_value_expressionContext ctx) {
+    if (checkIfExist(ctx.NULL())) {
+      return new NullLiteral();
+    } else {
+      return visitChildren(ctx);
+    }
+  }
+
+  @Override
+  public Expr visitParenthesized_value_expression(Parenthesized_value_expressionContext ctx) {
+    return visitValue_expression(ctx.value_expression());
+  }
+
+  @Override
+  public Expr visitBoolean_value_expression(Boolean_value_expressionContext ctx) {
+    Expr current = visitOr_predicate(ctx.or_predicate());
+    return current;
+  }
+
+  @Override
+  public Expr visitOr_predicate(Or_predicateContext ctx) {
+    Expr current = visitAnd_predicate(ctx.and_predicate());
+
+    Expr left;
+    Expr right;
+    for (int i = 0; i < ctx.or_predicate().size(); i++) {
+      left = current;
+      right = visitOr_predicate(ctx.or_predicate(i));
+      current = new BinaryOperator(OpType.Or, left, right);
+    }
+
+    return current;
+  }
+
+  @Override
+  public Expr visitAnd_predicate(And_predicateContext ctx) {
+    Expr current = visitBoolean_factor(ctx.boolean_factor());
+
+    Expr left;
+    Expr right;
+    for (int i = 0; i < ctx.and_predicate().size(); i++) {
+      left = current;
+      right = visitAnd_predicate(ctx.and_predicate(i));
+      current = new BinaryOperator(OpType.And, left, right);
+    }
+
+    return current;
+  }
+
+  @Override
+  public Expr visitBoolean_factor(Boolean_factorContext ctx) {
+    if (ctx.NOT() != null) {
+      return new NotExpr(visitBoolean_test(ctx.boolean_test()));
+    } else {
+      return visitBoolean_test(ctx.boolean_test());
+    }
+  }
+
+  @Override
+  public Expr visitBoolean_test(Boolean_testContext ctx) {
+    if (checkIfExist(ctx.is_clause())) {
+      Is_clauseContext isClauseContext = ctx.is_clause();
+      if (checkIfExist(isClauseContext.NOT())) {
+        if (checkIfExist(ctx.is_clause().truth_value().TRUE())) {
+          return new NotExpr(visitBoolean_primary(ctx.boolean_primary()));
+        } else {
+          return visitBoolean_primary(ctx.boolean_primary());
+        }
+      } else {
+        if (checkIfExist(ctx.is_clause().truth_value().TRUE())) {
+          return visitBoolean_primary(ctx.boolean_primary());
+        } else {
+          return new NotExpr(visitBoolean_primary(ctx.boolean_primary()));
+        }
+      }
+    } else {
+      return visitBoolean_primary(ctx.boolean_primary());
+    }
+  }
+
+  @Override
+  public Expr visitBoolean_primary(Boolean_primaryContext ctx) {
+    if (ctx.predicate() != null) {
+      return visitPredicate(ctx.predicate());
+    } else {
+      return visitBoolean_predicand(ctx.boolean_predicand());
+    }
+  }
+
+  @Override
+  public Expr visitBoolean_predicand(Boolean_predicandContext ctx) {
+    if (checkIfExist(ctx.nonparenthesized_value_expression_primary())) {
+      return visitNonparenthesized_value_expression_primary(ctx.nonparenthesized_value_expression_primary());
+    } else {
+      return visitBoolean_value_expression(ctx.parenthesized_boolean_value_expression().boolean_value_expression());
+    }
+  }
+
+  @Override
+  public Expr visitNonparenthesized_value_expression_primary(
+      Nonparenthesized_value_expression_primaryContext ctx) {
+    return visitChildren(ctx);
+  }
+
+  @Override
+  public Expr visitRow_value_predicand(Row_value_predicandContext ctx) {
+    if (checkIfExist(ctx.row_value_special_case())) {
+      return visitRow_value_special_case(ctx.row_value_special_case());
+    } else {
+      return visitRow_value_constructor_predicand(ctx.row_value_constructor_predicand());
+    }
+  }
+
+  @Override
+  public Expr visitRow_value_constructor_predicand(Row_value_constructor_predicandContext ctx) {
+    if (checkIfExist(ctx.boolean_predicand())) {
+      return visitBoolean_predicand(ctx.boolean_predicand());
+    } else {
+      return visitCommon_value_expression(ctx.common_value_expression());
+    }
+  }
+
+  @Override
+  public BinaryOperator visitComparison_predicate(Comparison_predicateContext ctx) {
+    TerminalNode operator = (TerminalNode) ctx.comp_op().getChild(0);
+    return new BinaryOperator(tokenToExprType(operator.getSymbol().getType()),
+        visitRow_value_predicand(ctx.left),
+        visitRow_value_predicand(ctx.right));
+  }
+
+  @Override
+  public Expr visitNumeric_value_expression(Numeric_value_expressionContext ctx) {
+    Expr current = visitTerm(ctx.term(0));
+
+    Expr left;
+    Expr right;
+    for (int i = 1; i < ctx.getChildCount(); i++) {
+      left = current;
+      TerminalNode operator = (TerminalNode) ctx.getChild(i++);
+      right = visitTerm((TermContext) ctx.getChild(i));
+
+      if (operator.getSymbol().getType() == PLUS) {
+        current = new BinaryOperator(OpType.Plus, left, right);
+      } else {
+        current = new BinaryOperator(OpType.Minus, left, right);
+      }
+    }
+
+    return current;
+  }
+
+  @Override
+  public Expr visitTerm(TermContext ctx) {
+    Expr current = visitFactor(ctx.factor(0));
+
+    Expr left;
+    Expr right;
+    for (int i = 1; i < ctx.getChildCount(); i++) {
+      left = current;
+      TerminalNode operator = (TerminalNode) ctx.getChild(i++);
+      right = visitFactor((FactorContext) ctx.getChild(i));
+
+      if (operator.getSymbol().getType() == MULTIPLY) {
+        current = new BinaryOperator(OpType.Multiply, left, right);
+      } else if (operator.getSymbol().getType() == DIVIDE) {
+        current = new BinaryOperator(OpType.Divide, left, right);
+      } else {
+        current = new BinaryOperator(OpType.Modular, left, right);
+      }
+    }
+
+    return current;
+  }
+
+  @Override
+  public Expr visitFactor(FactorContext ctx) {
+    Expr current = visitNumeric_primary(ctx.numeric_primary());
+    if (checkIfExist(ctx.sign()) && checkIfExist(ctx.sign().MINUS())) {
+      current = new SignedExpr(true, current);
+    }
+    return current;
+  }
+
+  @Override
+  public Expr visitNumeric_primary(Numeric_primaryContext ctx) {
+    Expr current = null;
+    if (checkIfExist(ctx.value_expression_primary())) {
+      current = visitValue_expression_primary(ctx.value_expression_primary());
+      for (int i = 0; i < ctx.CAST_EXPRESSION().size(); i++) {
+        current = new CastExpr(current, visitData_type(ctx.cast_target(i).data_type()));
+      }
+    } else if (checkIfExist(ctx.numeric_value_function())) {
+      current = visitNumeric_value_function(ctx.numeric_value_function());
+    }
+
+    return current;
+  }
+
+  public static OpType tokenToExprType(int tokenId) {
+    switch (tokenId) {
+      case UNION:
+        return OpType.Union;
+      case EXCEPT:
+        return OpType.Except;
+      case INTERSECT:
+        return OpType.Intersect;
+
+      case AND:
+        return OpType.And;
+      case OR:
+        return OpType.Or;
+
+      case EQUAL:
+        return OpType.Equals;
+      case NOT_EQUAL:
+        return OpType.NotEquals;
+      case LTH:
+        return OpType.LessThan;
+      case LEQ:
+        return OpType.LessThanOrEquals;
+      case GTH:
+        return OpType.GreaterThan;
+      case GEQ:
+        return OpType.GreaterThanOrEquals;
+
+      case MULTIPLY:
+        return OpType.Multiply;
+      case DIVIDE:
+        return OpType.Divide;
+      case MODULAR:
+        return OpType.Modular;
+      case PLUS:
+        return OpType.Plus;
+      case MINUS:
+        return OpType.Minus;
+
+      default:
+        throw new RuntimeException("Unknown Token Id: " + tokenId);
+    }
+  }
+
+  @Override
+  public InPredicate visitIn_predicate(In_predicateContext ctx) {
+    return new InPredicate(visitChildren(ctx.numeric_value_expression()),
+        visitIn_predicate_value(ctx.in_predicate_value()), ctx.NOT() != null);
+  }
+
+  @Override
+  public Expr visitIn_predicate_value(In_predicate_valueContext ctx) {
+    if (checkIfExist(ctx.in_value_list())) {
+      int size = ctx.in_value_list().row_value_predicand().size();
+      Expr [] exprs = new Expr[size];
+      for (int i = 0; i < size; i++) {
+        exprs[i] = visitRow_value_predicand(ctx.in_value_list().row_value_predicand(i));
+      }
+      return new ValueListExpr(exprs);
+    } else {
+      return new SimpleTableSubquery(visitChildren(ctx.table_subquery()));
+    }
+  }
+
+  @Override
+  public Expr visitArray(ArrayContext ctx) {
+    int size = ctx.numeric_value_expression().size();
+    Expr[] exprs = new Expr[size];
+    for (int i = 0; i < size; i++) {
+      exprs[i] = visit(ctx.numeric_value_expression(i));
+    }
+    return new ValueListExpr(exprs);
+  }
+
+  @Override
+  public Expr visitPattern_matching_predicate(Pattern_matching_predicateContext ctx) {
+    Expr predicand = visitChildren(ctx.row_value_predicand());
+    Expr pattern = new LiteralValue(stripQuote(ctx.Character_String_Literal().getText()),
+        LiteralType.String);
+
+    if (checkIfExist(ctx.pattern_matcher().negativable_matcher())) {
+      boolean not = ctx.pattern_matcher().NOT() != null;
+      Negativable_matcherContext matcher = ctx.pattern_matcher().negativable_matcher();
+      if (checkIfExist(matcher.LIKE())) {
+        return new PatternMatchPredicate(OpType.LikePredicate, not, predicand, pattern);
+      } else if (checkIfExist(matcher.ILIKE())) {
+        return new PatternMatchPredicate(OpType.LikePredicate, not, predicand, pattern, true);
+      } else if (checkIfExist(matcher.SIMILAR())) {
+        return new PatternMatchPredicate(OpType.SimilarToPredicate, not, predicand, pattern);
+      } else if (checkIfExist(matcher.REGEXP()) || checkIfExist(matcher.RLIKE())) {
+        return new PatternMatchPredicate(OpType.Regexp, not, predicand, pattern);
+      } else {
+        throw new TajoRuntimeException(new SQLSyntaxError("Unsupported predicate: " + matcher.getText()));
+      }
+    } else if (checkIfExist(ctx.pattern_matcher().regex_matcher())) {
+      Regex_matcherContext matcher = ctx.pattern_matcher().regex_matcher();
+      if (checkIfExist(matcher.Similar_To())) {
+        return new PatternMatchPredicate(OpType.Regexp, false, predicand, pattern, false);
+      } else if (checkIfExist(matcher.Not_Similar_To())) {
+        return new PatternMatchPredicate(OpType.Regexp, true, predicand, pattern, false);
+      } else if (checkIfExist(matcher.Similar_To_Case_Insensitive())) {
+        return new PatternMatchPredicate(OpType.Regexp, false, predicand, pattern, true);
+      } else if (checkIfExist(matcher.Not_Similar_To_Case_Insensitive())) {
+        return new PatternMatchPredicate(OpType.Regexp, true, predicand, pattern, true);
+      } else {
+        throw new TajoRuntimeException(new SQLSyntaxError("Unsupported predicate: " + matcher.getText()));
+      }
+    } else {
+      throw new TajoRuntimeException(new SQLSyntaxError("Unsupported predicate: " + ctx.pattern_matcher().getText()));
+    }
+  }
+
+  @Override
+  public IsNullPredicate visitNull_predicate(Null_predicateContext ctx) {
+    Expr predicand = visitRow_value_predicand(ctx.row_value_predicand());
+    return new IsNullPredicate(ctx.NOT() != null, predicand);
+  }
+
+  @Override
+  public ExistsPredicate visitExists_predicate(Exists_predicateContext ctx) {
+    return new ExistsPredicate(new SimpleTableSubquery(visitTable_subquery(ctx.table_subquery())), ctx.NOT() != null);
+  }
+
+  @Override
+  public ColumnReferenceExpr visitColumn_reference(Column_referenceContext ctx) {
+    String columnReferenceName = ctx.getText();
+    // find the last dot (.) position to separate a name into both a qualifier and name
+    int lastDotIdx = columnReferenceName.lastIndexOf(".");
+
+    if (lastDotIdx > 0) { // if any qualifier is given
+      String qualifier = columnReferenceName.substring(0, lastDotIdx);
+      String name = columnReferenceName.substring(lastDotIdx + 1, columnReferenceName.length());
+      return new ColumnReferenceExpr(qualifier, name);
+    } else {
+      return new ColumnReferenceExpr(ctx.getText());
+    }
+  }
+
+  @Override
+  public LiteralValue visitUnsigned_numeric_literal(@NotNull Unsigned_numeric_literalContext ctx) {
+    if (ctx.NUMBER() != null) {
+      long lValue = Long.parseLong(ctx.getText());
+      if (lValue >= Integer.MIN_VALUE && lValue <= Integer.MAX_VALUE) {
+        return new LiteralValue(ctx.getText(), LiteralType.Unsigned_Integer);
+      } else {
+        return new LiteralValue(ctx.getText(), LiteralType.Unsigned_Large_Integer);
+      }
+    } else {
+      return new LiteralValue(ctx.getText(), LiteralType.Unsigned_Float);
+    }
+  }
+
+  @Override
+  public GeneralSetFunctionExpr visitAggregate_function(Aggregate_functionContext ctx) {
+    if (ctx.COUNT() != null && ctx.MULTIPLY() != null) {
+      return new CountRowsFunctionExpr();
+    } else {
+      return visitGeneral_set_function(ctx.general_set_function());
+    }
+  }
+
+  @Override
+  public GeneralSetFunctionExpr visitGeneral_set_function(General_set_functionContext ctx) {
+    String signature = ctx.set_function_type().getText();
+    boolean distinct = checkIfExist(ctx.set_qualifier()) && checkIfExist(ctx.set_qualifier().DISTINCT());
+    Expr param = visitValue_expression(ctx.value_expression());
+
+    return new GeneralSetFunctionExpr(signature, distinct, new Expr [] {param});
+  }
+
+  @Override
+  public FunctionExpr visitRoutine_invocation(Routine_invocationContext ctx) {
+    String signature = ctx.function_name().getText();
+    FunctionExpr function = new FunctionExpr(signature);
+    if (ctx.sql_argument_list() != null) {
+      int numArgs = ctx.sql_argument_list().value_expression().size();
+      Expr[] argument_list = new Expr[numArgs];
+      for (int i = 0; i < numArgs; i++) {
+        argument_list[i] = visitValue_expression(ctx.sql_argument_list().
+            value_expression().get(i));
+      }
+
+      function.setParams(argument_list);
+    }
+    return function;
+  }
+
+  @Override
+  public NamedExpr visitDerived_column(Derived_columnContext ctx) {
+    NamedExpr target = new NamedExpr(visitValue_expression(ctx.value_expression()));
+    if (ctx.as_clause() != null) {
+      target.setAlias(ctx.as_clause().identifier().getText());
+    }
+    return target;
+  }
+
+  @Override
+  public NamedExpr visitQualified_asterisk(Qualified_asteriskContext ctx) {
+    QualifiedAsteriskExpr target = new QualifiedAsteriskExpr();
+    if (ctx.tb_name != null) {
+      target.setQualifier(ctx.tb_name.getText());
+    }
+
+    return new NamedExpr(target);
+  }
+
+  @Override
+  public Expr visitCharacter_string_type(Character_string_typeContext ctx) {
+    return new LiteralValue(stripQuote(ctx.getText()), LiteralType.String);
+  }
+
+  @Override
+  public Expr visitCharacter_value_expression(Character_value_expressionContext ctx) {
+    Expr current = visitCharacter_factor(ctx.character_factor(0));
+
+    Expr left;
+    Expr right;
+    for (int i = 1; i < ctx.getChildCount(); i++) {
+      left = current;
+      i++; // skip '||' operator
+      right = visitCharacter_factor((Character_factorContext) ctx.getChild(i));
+
+      if (left.getType() == OpType.Literal && right.getType() == OpType.Literal) {
+        current = new LiteralValue(((LiteralValue) left).getValue() + ((LiteralValue) right).getValue(),
+            LiteralType.String);
+      } else {
+        current = new BinaryOperator(OpType.Concatenate, left, right);
+      }
+    }
+
+    return current;
+  }
+
+
+  @Override
+  public Expr visitNumeric_value_function(Numeric_value_functionContext ctx) {
+    if (checkIfExist(ctx.extract_expression())) {
+      return visitExtract_expression(ctx.extract_expression());
+    }
+    if (checkIfExist(ctx.datetime_value_function())) {
+      return visitDatetime_value_function(ctx.datetime_value_function());
+    }
+    return null;
+  }
+
+  @Override
+  public Expr visitExtract_expression(Extract_expressionContext ctx) {
+    Expr extractTarget = new LiteralValue(ctx.extract_field_string.getText(), LiteralType.String);
+    Expr extractSource = visitDatetime_value_expression(ctx.extract_source().datetime_value_expression());
+//    if (checkIfExist(ctx.extract_source().column_reference())) {
+//      extractSource = visitColumn_reference(ctx.extract_source().column_reference());
+//    } else if (checkIfExist(ctx.extract_source().datetime_literal())) {
+//      extractSource = visitDatetime_literal(ctx.extract_source().datetime_literal());
+//    } else {
+//      return null;
+//    }
+
+
+    String functionName = "date_part";
+    Expr[] params = new Expr[]{extractTarget, extractSource};
+
+    return new FunctionExpr(functionName, params);
+  }
+
+  @Override
+  public Expr visitTrim_function(Trim_functionContext ctx) {
+    Expr trimSource = visitChildren(ctx.trim_operands().trim_source);
+    String functionName = "trim";
+    if (checkIfExist(ctx.trim_operands().FROM())) {
+      if (checkIfExist(ctx.trim_operands().trim_specification())) {
+        Trim_specificationContext specification = ctx.trim_operands().trim_specification();
+        if (checkIfExist(specification.LEADING())) {
+          functionName = "ltrim";
+        } else if (checkIfExist(specification.TRAILING())) {
+          functionName = "rtrim";
+        } else {
+          functionName = "trim";
+        }
+      }
+    }
+
+    Expr trimCharacters = null;
+    if (checkIfExist(ctx.trim_operands().trim_character)) {
+      trimCharacters = visitCharacter_value_expression(ctx.trim_operands().trim_character);
+    }
+
+    Expr[] params;
+    if (trimCharacters != null) {
+      params = new Expr[]{trimSource, trimCharacters};
+    } else {
+      params = new Expr[]{trimSource};
+    }
+
+    return new FunctionExpr(functionName, params);
+  }
+
+  @Override
+  public Expr visitCreate_index_statement(Create_index_statementContext ctx) {
+    String indexName = ctx.index_name.getText();
+    String tableName = ctx.table_name().getText();
+    Relation relation = new Relation(tableName);
+    SortSpec[] sortSpecs = buildSortSpecs(ctx.sort_specifier_list());
+    NamedExpr[] targets = new NamedExpr[sortSpecs.length];
+    Projection projection = new Projection();
+    int i = 0;
+    for (SortSpec sortSpec : sortSpecs) {
+      targets[i++] = new NamedExpr(sortSpec.getKey());
+    }
+    projection.setNamedExprs(targets);
+    projection.setChild(relation);
+
+    CreateIndex createIndex = new CreateIndex(indexName, sortSpecs);
+    if (checkIfExist(ctx.UNIQUE())) {
+      createIndex.setUnique(true);
+    }
+    if (checkIfExist(ctx.method_specifier())) {
+      String methodName = ctx.method_specifier().identifier().getText();
+      createIndex.setMethodSpec(new IndexMethodSpec(methodName));
+    }
+    if (checkIfExist(ctx.param_clause())) {
+      Map<String, String> params = getParams(ctx.param_clause());
+      createIndex.setParams(params);
+    }
+    if (checkIfExist(ctx.where_clause())) {
+      Selection selection = visitWhere_clause(ctx.where_clause());
+      selection.setChild(relation);
+      projection.setChild(selection);
+    }
+    if (checkIfExist(ctx.LOCATION())) {
+      createIndex.setIndexPath(stripQuote(ctx.path.getText()));
+    }
+    createIndex.setChild(projection);
+    return createIndex;
+  }
+
+  @Override
+  public Expr visitDrop_index_statement(Drop_index_statementContext ctx) {
+    String indexName = ctx.identifier().getText();
+    return new DropIndex(indexName);
+  }
+
+  @Override
+  public Expr visitDatabase_definition(@NotNull Database_definitionContext ctx) {
+    return new CreateDatabase(ctx.identifier().getText(), null, checkIfExist(ctx.if_not_exists()));
+  }
+
+  @Override
+  public Expr visitDrop_database_statement(@NotNull Drop_database_statementContext ctx) {
+    return new DropDatabase(ctx.identifier().getText(), checkIfExist(ctx.if_exists()));
+  }
+
+  @Override
+  public Expr visitCreate_table_statement(Create_table_statementContext ctx) {
+    String tableName = ctx.table_name(0).getText();
+    CreateTable createTable = new CreateTable(tableName, checkIfExist(ctx.if_not_exists()));
+    if(checkIfExist(ctx.LIKE()))  {
+      createTable.setLikeParentTable(ctx.like_table_name.getText());
+      return createTable;
+    }
+
+    if (checkIfExist(ctx.EXTERNAL())) {
+      createTable.setExternal();
+
+      ColumnDefinition[] elements = getDefinitions(ctx.table_elements());
+      String storageType = ctx.storage_type.getText();
+      createTable.setTableElements(elements);
+      createTable.setStorageType(storageType);
+
+      if (checkIfExist(ctx.LOCATION())) {
+        String uri = stripQuote(ctx.uri.getText());
+        createTable.setLocation(uri);
+      }
+    } else {
+      if (checkIfExist(ctx.table_elements())) {
+        ColumnDefinition[] elements = getDefinitions(ctx.table_elements());
+        createTable.setTableElements(elements);
+      }
+
+      if (checkIfExist(ctx.TABLESPACE())) {
+        String spaceName = ctx.spacename.getText();
+        createTable.setTableSpaceName(spaceName);
+      }
+
+      if (checkIfExist(ctx.USING())) {
+        String fileType = ctx.storage_type.getText();
+        createTable.setStorageType(fileType);
+      }
+
+      if (checkIfExist(ctx.query_expression())) {
+        Expr subquery = visitQuery_expression(ctx.query_expression());
+        createTable.setSubQuery(subquery);
+      }
+    }
+
+    if (checkIfExist(ctx.param_clause())) {
+      Map<String, String> params = escapeTableMeta(getParams(ctx.param_clause()));
+      createTable.setParams(params);
+    }
+
+    if (checkIfExist(ctx.table_partitioning_clauses())) {
+      PartitionMethodDescExpr partitionMethodDesc =
+          parseTablePartitioningClause(ctx.table_partitioning_clauses());
+      createTable.setPartitionMethod(partitionMethodDesc);
+    }
+    return createTable;
+  }
+
+  @Override
+  public Expr visitTruncate_table_statement(@NotNull Truncate_table_statementContext ctx) {
+    List<Table_nameContext> tableNameContexts = ctx.table_name();
+    List<String> tableNames = new ArrayList<String>();
+
+    for (Table_nameContext eachTableNameContext: tableNameContexts) {
+      tableNames.add(eachTableNameContext.getChild(0).getText());
+    }
+
+    return new TruncateTable(tableNames);
+  }
+
+  private ColumnDefinition[] getDefinitions(Table_elementsContext ctx) {
+    int size = ctx.field_element().size();
+    ColumnDefinition[] elements = new ColumnDefinition[size];
+    for (int i = 0; i < size; i++) {
+      String name = ctx.field_element(i).name.getText();
+
+      String dataTypeName = ctx.field_element(i).field_type().data_type().getText();
+      DataTypeExpr typeDef = visitData_type(ctx.field_element(i).field_type().data_type());
+      Preconditions.checkNotNull(typeDef, dataTypeName + " is not handled correctly");
+      elements[i] = new ColumnDefinition(name, typeDef);
+    }
+
+    return elements;
+  }
+
+  public PartitionMethodDescExpr parseTablePartitioningClause(Table_partitioning_clausesContext ctx) {
+
+    if (checkIfExist(ctx.range_partitions())) { // For Range Partition
+      Range_partitionsContext rangePartitionsContext = ctx.range_partitions();
+      List<Range_value_clauseContext> rangeValueClause = rangePartitionsContext.
+          range_value_clause_list().range_value_clause();
+
+      List<RangePartitionSpecifier> specifiers = Lists.newArrayList();
+
+      for (Range_value_clauseContext rangeValue : rangeValueClause) {
+        if (checkIfExist(rangeValue.MAXVALUE())) { // LESS THAN (MAXVALUE)
+          specifiers.add(new RangePartitionSpecifier(rangeValue.partition_name().getText()));
+        } else { // LESS THAN (expr)
+          specifiers.add(new RangePartitionSpecifier(rangeValue.partition_name().getText(),
+              visitValue_expression(rangeValue.value_expression())));
+        }
+      }
+      return new CreateTable.RangePartition(buildColumnReferenceList(ctx.range_partitions().column_reference_list()),
+          specifiers);
+
+    } else if (checkIfExist(ctx.hash_partitions())) { // For Hash Partition
+      Hash_partitionsContext hashPartitions = ctx.hash_partitions();
+
+      if (checkIfExist(hashPartitions.hash_partitions_by_quantity())) { // PARTITIONS (num)
+        return new HashPartition(buildColumnReferenceList(hashPartitions.column_reference_list()),
+            visitNumeric_value_expression(hashPartitions.hash_partitions_by_quantity().quantity));
+
+      } else { // ( PARTITION part_name , ...)
+        List<CreateTable.PartitionSpecifier> specifiers = Lists.newArrayList();
+        for (Individual_hash_partitionContext partition :
+            hashPartitions.individual_hash_partitions().individual_hash_partition()) {
+          specifiers.add(new CreateTable.PartitionSpecifier(partition.partition_name().getText()));
+        }
+        return new HashPartition(buildColumnReferenceList(hashPartitions.column_reference_list()), specifiers);
+      }
+
+    } else if (checkIfExist(ctx.list_partitions())) { // For List Partition
+      List_partitionsContext listPartitions = ctx.list_partitions();
+      List<List_value_partitionContext> partitions = listPartitions.list_value_clause_list().list_value_partition();
+      List<ListPartitionSpecifier> specifiers = Lists.newArrayList();
+
+      for (List_value_partitionContext listValuePartition : partitions) {
+        int size = listValuePartition.in_value_list().row_value_predicand().size();
+        Expr [] exprs = new Expr[size];
+        for (int i = 0; i < size; i++) {
+          exprs[i] = visitRow_value_predicand(listValuePartition.in_value_list().row_value_predicand(i));
+        }
+        specifiers.add(new ListPartitionSpecifier(listValuePartition.partition_name().getText(),
+            new ValueListExpr(exprs)));
+      }
+      return new ListPartition(buildColumnReferenceList(ctx.list_partitions().column_reference_list()), specifiers);
+
+    } else if (checkIfExist(ctx.column_partitions())) { // For Column Partition (Hive Style)
+      return new CreateTable.ColumnPartition(getDefinitions(ctx.column_partitions().table_elements()));
+    } else {
+      throw new TajoRuntimeException(new SQLSyntaxError("Invalid Partition Type: " + ctx.toStringTree()));
+    }
+  }
+
+  @Override
+  public DataTypeExpr visitData_type(Data_typeContext ctx) {
+    Predefined_typeContext predefined_type = ctx.predefined_type();
+
+    DataTypeExpr typeDefinition = null;
+
+    // CHAR -> FIXED   CHAR
+    //      |- VARYING CHAR
+    // TEXT
+    if (checkIfExist(predefined_type.character_string_type())) {
+
+      Character_string_typeContext character_string_type = predefined_type.character_string_type();
+
+
+      if ((checkIfExist(character_string_type.CHARACTER()) || checkIfExist(character_string_type.CHAR())) &&
+          !checkIfExist(character_string_type.VARYING())) {
+
+        typeDefinition = new DataTypeExpr(Type.CHAR.name());
+
+        if (character_string_type.type_length() != null) {
+          typeDefinition.setLengthOrPrecision(
+              Integer.parseInt(character_string_type.type_length().NUMBER().getText()));
+        }
+
+      } else if (checkIfExist(character_string_type.VARCHAR()) || checkIfExist(character_string_type.VARYING())) {
+
+        typeDefinition = new DataTypeExpr(Type.VARCHAR.name());
+
+        if (character_string_type.type_length() != null) {
+          typeDefinition.setLengthOrPrecision(
+              Integer.parseInt(character_string_type.type_length().NUMBER().getText()));
+        }
+
+      } else if (checkIfExist(character_string_type.TEXT())) {
+        typeDefinition = new DataTypeExpr(Type.TEXT.name());
+      }
+
+    // NCHAR
+    } else if (checkIfExist(predefined_type.national_character_string_type())) {
+
+      National_character_string_typeContext nchar_type = predefined_type.national_character_string_type();
+
+      if ((checkIfExist(nchar_type.CHAR()) || checkIfExist(nchar_type.CHARACTER()) ||
+          checkIfExist(nchar_type.NCHAR()) && !checkIfExist(nchar_type.VARYING()))) {
+
+        typeDefinition = new DataTypeExpr(Type.NCHAR.name());
+
+      } else if (checkIfExist(nchar_type.NVARCHAR()) || checkIfExist(nchar_type.VARYING())) {
+
+        typeDefinition = new DataTypeExpr(Type.NVARCHAR.name());
+      }
+
+      // if a length is given
+      if (checkIfExist(nchar_type.type_length())) {
+        typeDefinition.setLengthOrPrecision(Integer.parseInt(nchar_type.type_length().NUMBER().getText()));
+      }
+
+    // BLOB types
+    } else if (checkIfExist(predefined_type.binary_large_object_string_type())) {
+
+      Binary_large_object_string_typeContext blob_type = predefined_type.binary_large_object_string_type();
+
+      typeDefinition = new DataTypeExpr(Type.BLOB.name());
+
+      if (checkIfExist(blob_type.type_length())) {
+        typeDefinition.setLengthOrPrecision(Integer.parseInt(blob_type.type_length().NUMBER().getText()));
+      }
+
+    // NUMERIC types
+    } else if (checkIfExist(predefined_type.numeric_type())) {
+      // exact number
+      if (checkIfExist(predefined_type.numeric_type().exact_numeric_type())) {
+
+        Exact_numeric_typeContext exactType = predefined_type.numeric_type().exact_numeric_type();
+
+        if (checkIfExist(exactType.TINYINT()) || checkIfExist(exactType.INT1())) {
+          typeDefinition = new DataTypeExpr(Type.INT1.name());
+
+        } else if (checkIfExist(exactType.INT2()) || checkIfExist(exactType.SMALLINT())) {
+          typeDefinition = new DataTypeExpr(Type.INT2.name());
+
+        } else if (checkIfExist(exactType.INT4()) ||
+            checkIfExist(exactType.INTEGER()) ||
+            checkIfExist(exactType.INT())) {
+          typeDefinition = new DataTypeExpr(Type.INT4.name());
+
+        } else if (checkIfExist(exactType.INT8()) || checkIfExist(exactType.BIGINT()) ) {
+          typeDefinition = new DataTypeExpr(Type.INT8.name());
+
+        } else if (checkIfExist(exactType.NUMERIC()) ||
+            checkIfExist(exactType.DECIMAL()) ||
+            checkIfExist(exactType.DEC())) {
+          typeDefinition = new DataTypeExpr(Type.NUMERIC.name());
+
+          if (checkIfExist(exactType.precision_param())) {
+            typeDefinition.setLengthOrPrecision(Integer.parseInt(exactType.precision_param().precision.getText()));
+
+            if (checkIfExist(exactType.precision_param().scale)) {
+              typeDefinition.setScale(Integer.parseInt(exactType.precision_param().scale.getText()));
+            }
+          }
+        }
+
+
+      } else { // approximate number
+        Approximate_numeric_typeContext approximateType = predefined_type.numeric_type().approximate_numeric_type();
+        if (checkIfExist(approximateType.FLOAT()) ||
+            checkIfExist(approximateType.FLOAT4()) ||
+            checkIfExist(approximateType.REAL())) {
+          typeDefinition = new DataTypeExpr(Type.FLOAT4.name());
+
+        } else if (checkIfExist(approximateType.FLOAT8()) || checkIfExist(approximateType.DOUBLE())) {
+          typeDefinition = new DataTypeExpr(Type.FLOAT8.name());
+        }
+      }
+
+    } else if (checkIfExist(predefined_type.boolean_type())) {
+      typeDefinition = new DataTypeExpr(Type.BOOLEAN.name());
+
+    } else if (checkIfExist(predefined_type.datetime_type())) {
+
+      Datetime_typeContext dateTimeType = predefined_type.datetime_type();
+      if (checkIfExist(dateTimeType.DATE())) {
+        typeDefinition = new DataTypeExpr(Type.DATE.name());
+
+      } else if (checkIfExist(dateTimeType.TIME(0))) {
+        if (checkIfExist(dateTimeType.ZONE())) {
+          typeDefinition = new DataTypeExpr(Type.TIMEZ.name());
+        } else {
+          typeDefinition = new DataTypeExpr(Type.TIME.name());
+        }
+
+      } else if (checkIfExist(dateTimeType.TIMETZ())) {
+        typeDefinition = new DataTypeExpr(Type.TIMEZ.name());
+
+      } else if (checkIfExist(dateTimeType.TIMESTAMP())) {
+         if (checkIfExist(dateTimeType.ZONE())) {
+           typeDefinition = new DataTypeExpr(Type.TIMESTAMPZ.name());
+         }  else {
+           typeDefinition = new DataTypeExpr(Type.TIMESTAMP.name());
+         }
+
+      } else if (checkIfExist(dateTimeType.TIMESTAMPTZ())) {
+        typeDefinition = new DataTypeExpr(Type.TIMESTAMPZ.name());
+      }
+
+      // bit data types
+    } else if (predefined_type.bit_type() != null) {
+      Bit_typeContext bitType = predefined_type.bit_type();
+
+      if (checkIfExist(bitType.VARBIT()) || checkIfExist(bitType.VARYING())) {
+        typeDefinition = new DataTypeExpr(Type.VARBIT.name());
+
+      } else {
+        typeDefinition = new DataTypeExpr(Type.BIT.name());
+      }
+
+      if (checkIfExist(bitType.type_length())) {
+        typeDefinition.setLengthOrPrecision(
+            Integer.parseInt(bitType.type_length().NUMBER().getText()));
+      }
+
+
+      // binary data types
+    } else if (checkIfExist(predefined_type.binary_type())) {
+      Binary_typeContext binaryType = predefined_type.binary_type();
+
+      if (checkIfExist(binaryType.VARBINARY()) || checkIfExist(binaryType.VARYING())) {
+        typeDefinition = new DataTypeExpr(Type.VARBINARY.name());
+      } else {
+        typeDefinition = new DataTypeExpr(Type.BINARY.name());
+      }
+
+
+      if (checkIfExist(binaryType.type_length())) {
+        typeDefinition.setLengthOrPrecision(Integer.parseInt(binaryType.type_length().NUMBER().getText()));
+      }
+
+      // inet
+    } else if (checkIfExist(predefined_type.network_type())) {
+      typeDefinition = new DataTypeExpr(Type.INET4.name());
+
+
+    } else if (checkIfExist(predefined_type.record_type())) {
+      ColumnDefinition [] nestedRecordDefine = getDefinitions(predefined_type.record_type().table_elements());
+      typeDefinition = new DataTypeExpr(new DataTypeExpr.RecordType(nestedRecordDefine));
+
+    } else if (checkIfExist(predefined_type.map_type())) {
+      Map_typeContext mapTypeContext = predefined_type.map_type();
+      typeDefinition = new DataTypeExpr(
+          new MapType(visitData_type(mapTypeContext.key_type), visitData_type(mapTypeContext.value_type)));
+    }
+
+    return typeDefinition;
+  }
+
+  @Override
+  public Expr visitInsert_statement(Insert_statementContext ctx) {
+    Insert insertExpr = new Insert();
+
+    if (ctx.OVERWRITE() != null) {
+      insertExpr.setOverwrite();
+    }
+
+    if (ctx.table_name() != null) {
+      insertExpr.setTableName(ctx.table_name().getText());
+
+      if (ctx.column_reference_list() != null) {
+        ColumnReferenceExpr [] targetColumns =
+            new ColumnReferenceExpr[ctx.column_reference_list().column_reference().size()];
+
+        for (int i = 0; i < targetColumns.length; i++) {
+          targetColumns[i] = visitColumn_reference(ctx.column_reference_list().column_reference(i));
+        }
+
+        insertExpr.setTargetColumns(targetColumns);
+      }
+    }
+
+    if (ctx.LOCATION() != null) {
+      insertExpr.setLocation(stripQuote(ctx.path.getText()));
+
+      if (ctx.USING() != null) {
+        insertExpr.setStorageType(ctx.storage_type.getText());
+
+        if (ctx.param_clause() != null) {
+          insertExpr.setParams(escapeTableMeta(getParams(ctx.param_clause())));
+        }
+      }
+    }
+
+    insertExpr.setSubQuery(visitQuery_expression(ctx.query_expression()));
+
+    Preconditions.checkState(insertExpr.hasTableName() || insertExpr.hasLocation(),
+        "Either a table name or a location should be given.");
+    Preconditions.checkState(insertExpr.hasTableName() ^ insertExpr.hasLocation(),
+        "A table name and a location cannot coexist.");
+    return insertExpr;
+  }
+
+  @Override
+  public Expr visitDrop_table_statement(Drop_table_statementContext ctx) {
+    return new DropTable(ctx.table_name().getText(), checkIfExist(ctx.if_exists()), checkIfExist(ctx.PURGE()));
+  }
+
+
+  private Map<String, String> getParams(Param_clauseContext ctx) {
+    Map<String, String> params = new HashMap<String, String>();
+    for (int i = 0; i < ctx.param().size(); i++) {
+      params.put(stripQuote(ctx.param(i).key.getText()), stripQuote(ctx.param(i).value.getText()));
+    }
+
+    return params;
+  }
+
+  public Map<String, String> escapeTableMeta(Map<String, String> map) {
+    Map<String, String> params = new HashMap<String, String>();
+    for (Map.Entry<String, String> entry : map.entrySet()) {
+      if (entry.getKey().equals(StorageConstants.TEXT_DELIMITER)) {
+        params.put(StorageConstants.TEXT_DELIMITER, StringUtils.unicodeEscapedDelimiter(entry.getValue()));
+      } else {
+        params.put(entry.getKey(), entry.getValue());
+      }
+    }
+    return params;
+  }
+
+  private static String stripQuote(String str) {
+    return str.substring(1, str.length() - 1);
+  }
+
+  @Override
+  public Expr visitCast_specification(Cast_specificationContext ctx) {
+    Expr operand = visitChildren(ctx.cast_operand());
+    DataTypeExpr castTarget = visitData_type(ctx.cast_target().data_type());
+    return new CastExpr(operand, castTarget);
+  }
+
+  @Override
+  public Expr visitUnsigned_value_specification(@NotNull Unsigned_value_specificationContext ctx) {
+    return visitChildren(ctx);
+  }
+
+  @Override
+  public Expr visitUnsigned_literal(@NotNull Unsigned_literalContext ctx) {
+    if (checkIfExist(ctx.unsigned_numeric_literal())) {
+      return visitUnsigned_numeric_literal(ctx.unsigned_numeric_literal());
+    } else {
+      return visitGeneral_literal(ctx.general_literal());
+    }
+  }
+
+  @Override
+  public Expr visitGeneral_literal(General_literalContext ctx) {
+    if (checkIfExist(ctx.Character_String_Literal())) {
+      return new LiteralValue(stripQuote(ctx.Character_String_Literal().getText()), LiteralType.String);
+    } else if (checkIfExist(ctx.datetime_literal())) {
+      return visitDatetime_literal(ctx.datetime_literal());
+    } else {
+      return new BooleanLiteral(checkIfExist(ctx.boolean_literal().TRUE()));
+    }
+  }
+
+  @Override
+  public Expr visitDatetime_literal(@NotNull Datetime_literalContext ctx) {
+    if (checkIfExist(ctx.time_literal())) {
+      return visitTime_literal(ctx.time_literal());
+    } else if (checkIfExist(ctx.date_literal())) {
+      return visitDate_literal(ctx.date_literal());
+    } else if (checkIfExist(ctx.interval_literal())) {
+      return visitInterval_literal(ctx.interval_literal());
+    } else {
+      return visitTimestamp_literal(ctx.timestamp_literal());
+    }
+  }
+
+  @Override
+  public Expr visitTime_literal(Time_literalContext ctx) {
+    String timePart = stripQuote(ctx.time_string.getText());
+    return new TimeLiteral(parseTime(timePart));
+  }
+
+  @Override
+  public Expr visitDate_literal(Date_literalContext ctx) {
+    String datePart = stripQuote(ctx.date_string.getText());
+    return new DateLiteral(parseDate(datePart));
+  }
+
+  @Override
+  public Expr visitTimestamp_literal(Timestamp_literalContext ctx) {
+    String timestampStr = stripQuote(ctx.timestamp_string.getText());
+    String[] parts = timestampStr.split(" ");
+    String datePart = parts[0];
+    String timePart = parts[1];
+    return new TimestampLiteral(parseDate(datePart), parseTime(timePart));
+  }
+
+  @Override
+  public Expr visitInterval_literal(@NotNull Interval_literalContext ctx) {
+    String intervalStr = stripQuote(ctx.interval_string.getText());
+    return new IntervalLiteral(intervalStr);
+  }
+
+  @Override
+  public Expr visitDatetime_value_expression(@NotNull Datetime_value_expressionContext ctx) {
+    return visitDatetime_term(ctx.datetime_term());
+  }
+
+  @Override
+  public Expr visitDatetime_term(@NotNull Datetime_termContext ctx) {
+    return visitDatetime_factor(ctx.datetime_factor());
+  }
+
+  @Override
+  public Expr visitDatetime_factor(@NotNull Datetime_factorContext ctx) {
+    return visitDatetime_primary(ctx.datetime_primary());
+  }
+
+  @Override
+  public Expr visitDatetime_primary(@NotNull Datetime_primaryContext ctx) {
+    if (checkIfExist(ctx.value_expression_primary())) {
+      return visitValue_expression_primary(ctx.value_expression_primary());
+    } else {
+      return visitDatetime_value_function(ctx.datetime_value_function());
+    }
+  }
+
+  @Override
+  public Expr visitDatetime_value_function(@NotNull Datetime_value_functionContext ctx) {
+    if (checkIfExist(ctx.current_date_value_function())) {
+      return visitCurrent_date_value_function(ctx.current_date_value_function());
+    } else if (checkIfExist(ctx.current_time_value_function())) {
+      return visitCurrent_time_value_function(ctx.current_time_value_function());
+    } else {
+      return visitCurrent_timestamp_value_function(ctx.current_timestamp_value_function());
+    }
+  }
+
+  @Override
+  public Expr visitCurrent_date_value_function(@NotNull Current_date_value_functionContext ctx) {
+    String functionName = "current_date";
+    Expr[] params = new Expr[]{};
+    return new FunctionExpr(functionName, params);
+  }
+
+  @Override
+  public Expr visitCurrent_time_value_function(@NotNull Current_time_value_functionContext ctx) {
+    String functionName = "current_time";
+    Expr[] params = new Expr[]{};
+    return new FunctionExpr(functionName, params);
+  }
+
+  @Override
+  public Expr visitCurrent_timestamp_value_function(@NotNull Current_timestamp_value_functionContext ctx) {
+    String functionName = "now";
+    Expr[] params = new Expr[]{};
+    return new FunctionExpr(functionName, params);
+  }
+
+  private DateValue parseDate(String datePart) {
+    // e.g., 1980-04-01
+    String[] parts = datePart.split("-");
+    return new DateValue(parts[0], parts[1], parts[2]);
+  }
+
+  private TimeValue parseTime(String timePart) {
+    // e.g., 12:01:50.399
+    String[] parts = timePart.split(":");
+
+    TimeValue time;
+    boolean hasFractionOfSeconds = (parts.length > 2 && parts[2].indexOf('.') > 0);
+    if (hasFractionOfSeconds) {
+      String[] secondsParts = parts[2].split("\\.");
+      time = new TimeValue(parts[0], parts[1], secondsParts[0]);
+      if (secondsParts.length == 2) {
+        time.setSecondsFraction(secondsParts[1]);
+      }
+    } else {
+      time = new TimeValue(parts[0],
+          (parts.length > 1 ? parts[1] : "0"),
+          (parts.length > 2 ? parts[2] : "0"));
+    }
+    return time;
+  }
+
+  @Override
+  public Expr visitAlter_tablespace_statement(@NotNull Alter_tablespace_statementContext ctx) {
+    AlterTablespace alter = new AlterTablespace(ctx.space_name.getText());
+    alter.setLocation(stripQuote(ctx.uri.getText()));
+    return alter;
+  }
+
+  @Override
+  public Expr visitAlter_table_statement(Alter_table_statementContext ctx) {
+
+    final List<Table_nameContext> tables = ctx.table_name();
+
+    final AlterTable alterTable = new AlterTable(tables.get(0).getText());
+
+    if (tables.size() == 2) {
+      alterTable.setNewTableName(tables.get(1).getText());
+    }
+
+    if (checkIfExist(ctx.column_name()) && ctx.column_name().size() == 2) {
+      final List<Column_nameContext> columns = ctx.column_name();
+      alterTable.setColumnName(columns.get(0).getText());
+      alterTable.setNewColumnName(columns.get(1).getText());
+    }
+
+    Field_elementContext field_elementContext = ctx.field_element();
+    if (checkIfExist(field_elementContext)) {
+      final String name = field_elementContext.name.getText();
+      final DataTypeExpr typeDef = visitData_type(field_elementContext.field_type().data_type());
+      final ColumnDefinition columnDefinition = new ColumnDefinition(name, typeDef);
+      alterTable.setAddNewColumn(columnDefinition);
+    }
+
+    if (checkIfExist(ctx.partition_column_value_list())) {
+      List<Partition_column_valueContext> columnValueList = ctx.partition_column_value_list().partition_column_value();
+      int size = columnValueList.size();
+      ColumnReferenceExpr[] columns = new ColumnReferenceExpr[size];
+      Expr[] values = new Expr[size];
+      for (int i = 0; i < size; i++) {
+        Partition_column_valueContext columnValue = columnValueList.get(i);
+        columns[i] = new ColumnReferenceExpr(columnValue.identifier().getText());
+        values[i] = visitRow_value_predicand(columnValue.row_value_predicand());
+      }
+      alterTable.setColumns(columns);
+      alterTable.setValues(values);
+      if (ctx.LOCATION() != null) {
+        String path = stripQuote(ctx.path.getText());
+        alterTable.setLocation(path);
+      }
+      alterTable.setPurge(checkIfExist(ctx.PURGE()));
+      alterTable.setIfNotExists(checkIfExist(ctx.if_not_exists()));
+      alterTable.setIfExists(checkIfExist(ctx.if_exists()));
+    }
+
+    if (checkIfExist(ctx.property_list())) {
+      alterTable.setParams(getProperties(ctx.property_list()));
+    }
+
+    alterTable.setAlterTableOpType(determineAlterTableType(ctx));
+
+    return alterTable;
+  }
+
+  private Map<String, String> getProperties(Property_listContext ctx) {
+    Map<String, String> params = new HashMap<String, String>();
+    for (int i = 0; i < ctx.property().size(); i++) {
+      params.put(stripQuote(ctx.property(i).key.getText()), stripQuote(ctx.property(i).value.getText()));
+    }
+
+    return params;
+  }
+
+  private AlterTableOpType determineAlterTableType(Alter_table_statementContext ctx) {
+
+    final int RENAME_MASK = 00000001;
+    final int COLUMN_MASK = 00000010;
+    final int TO_MASK = 00000100;
+    final int ADD_MASK = 00001000;
+    final int DROP_MASK = 00001001;
+    final int PARTITION_MASK = 00000020;
+    final int SET_MASK = 00000002;
+    final int PROPERTY_MASK = 00010000;
+
+    int val = 00000000;
+
+    for (int idx = 1; idx < ctx.getChildCount(); idx++) {
+
+      if (ctx.getChild(idx) instanceof TerminalNode) {
+        switch (((TerminalNode) ctx.getChild(idx)).getSymbol().getType()) {
+          case RENAME:
+            val = val | RENAME_MASK;
+            break;
+          case COLUMN:
+            val = val | COLUMN_MASK;
+            break;
+          case TO:
+            val = val | TO_MASK;
+            break;
+          case ADD:
+            val = val | ADD_MASK;
+            break;
+          case DROP:
+            val = val | DROP_MASK;
+            break;
+          case PARTITION:
+            val = val | PARTITION_MASK;
+            break;
+          case SET:
+            val = val | SET_MASK;
+            break;
+          case PROPERTY:
+            val = val | PROPERTY_MASK;
+            break;
+          default:
+            break;
+        }
+      }
+    }
+    return evaluateAlterTableOperationTye(val);
+  }
+
+  private AlterTableOpType evaluateAlterTableOperationTye(final int value) {
+
+    switch (value) {
+      case 65:
+        return AlterTableOpType.RENAME_TABLE;
+      case 73:
+        return AlterTableOpType.RENAME_COLUMN;
+      case 520:
+        return AlterTableOpType.ADD_COLUMN;
+      case 528:
+        return AlterTableOpType.ADD_PARTITION;
+      case 529:
+        return AlterTableOpType.DROP_PARTITION;
+      case 4098:
+        return AlterTableOpType.SET_PROPERTY;
+      default:
+        return null;
+    }
+  }
+}

http://git-wip-us.apache.org/repos/asf/tajo/blob/33b8893f/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLErrorListener.java
----------------------------------------------------------------------
diff --git a/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLErrorListener.java b/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLErrorListener.java
new file mode 100644
index 0000000..e960844
--- /dev/null
+++ b/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLErrorListener.java
@@ -0,0 +1,38 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.parser.sql;
+
+import org.antlr.v4.runtime.*;
+import org.apache.commons.lang.StringUtils;
+
+public class SQLErrorListener extends BaseErrorListener {
+  public void syntaxError(Recognizer<?, ?> recognizer,
+                          Object offendingSymbol,
+                          int line, int charPositionInLine,
+                          String msg,
+                          RecognitionException e) {
+    CommonTokenStream tokens = (CommonTokenStream) recognizer.getInputStream();
+    String input = tokens.getTokenSource().getInputStream().toString();
+    Token token = (Token) offendingSymbol;
+    String[] lines = StringUtils.splitPreserveAllTokens(input, '\n');
+    String errorLine = lines[line - 1];
+
+    throw new SQLParseError(token, line, charPositionInLine, msg, errorLine);
+  }
+}

http://git-wip-us.apache.org/repos/asf/tajo/blob/33b8893f/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLErrorStrategy.java
----------------------------------------------------------------------
diff --git a/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLErrorStrategy.java b/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLErrorStrategy.java
new file mode 100644
index 0000000..236b854
--- /dev/null
+++ b/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLErrorStrategy.java
@@ -0,0 +1,66 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.parser.sql;
+
+import org.antlr.v4.runtime.*;
+import org.antlr.v4.runtime.misc.NotNull;
+
+public class SQLErrorStrategy extends DefaultErrorStrategy {
+
+  @Override
+  public void reportError(Parser recognizer, RecognitionException e) {
+    // if we've already reported an error and have not matched a token
+    // yet successfully, don't report any errors.
+    if (inErrorRecoveryMode(recognizer)) {
+      return; // don't report spurious errors
+    }
+    beginErrorCondition(recognizer);
+    if (e instanceof NoViableAltException) {
+      reportNoViableAltException(recognizer, (NoViableAltException) e);
+    } else if (e instanceof InputMismatchException) {
+      reportInputMismatchException(recognizer, (InputMismatchException) e);
+    } else if (e instanceof FailedPredicateException) {
+      reportFailedPredicate(recognizer, (FailedPredicateException) e);
+    } else {
+      recognizer.notifyErrorListeners(e.getOffendingToken(), e.getMessage(), e);
+    }
+  }
+
+  protected void reportNoViableAltException(@NotNull Parser recognizer, @NotNull NoViableAltException e) {
+    TokenStream tokens = recognizer.getInputStream();
+    String msg;
+    Token token = e.getStartToken();
+    if (tokens != null) {
+      if (tokens.LT(-1) != null && token.getType() == Token.EOF) {
+        token = tokens.LT(-1);
+      }
+      msg = "syntax error at or near " + getTokenErrorDisplay(token);
+    } else {
+      msg = "no viable alternative at input " + escapeWSAndQuote("<unknown input>");
+    }
+    recognizer.notifyErrorListeners(token, msg, e);
+  }
+
+  protected void reportInputMismatchException(@NotNull Parser recognizer,
+                                              @NotNull InputMismatchException e) {
+    String msg = "mismatched input " + getTokenErrorDisplay(e.getOffendingToken()) +
+        " expecting " + e.getExpectedTokens().toString(recognizer.getTokenNames());
+    recognizer.notifyErrorListeners(e.getOffendingToken(), msg, e);
+  }
+}

http://git-wip-us.apache.org/repos/asf/tajo/blob/33b8893f/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLParseError.java
----------------------------------------------------------------------
diff --git a/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLParseError.java b/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLParseError.java
new file mode 100644
index 0000000..f0568a5
--- /dev/null
+++ b/tajo-core/src/main/java/org/apache/tajo/parser/sql/SQLParseError.java
@@ -0,0 +1,107 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.tajo.parser.sql;
+
+
+import org.antlr.v4.runtime.Token;
+import org.apache.commons.lang.StringUtils;
+
+public class SQLParseError extends RuntimeException {
+  private String header;
+  private String errorLine;
+  private int charPositionInLine;
+  private int line;
+  private Token offendingToken;
+  private String detailedMessage;
+
+  public SQLParseError(Token offendingToken,
+                       int line, int charPositionInLine,
+                       String msg,
+                       String errorLine) {
+    super(msg);
+    this.offendingToken = offendingToken;
+    this.charPositionInLine = charPositionInLine;
+    this.line = line;
+    this.errorLine = errorLine;
+    this.header = msg;
+  }
+
+  @Override
+  public String getMessage() {
+    if (detailedMessage == null) {
+      if (offendingToken != null) {
+        detailedMessage = getDetailedMessageWithLocation();
+      } else {
+        StringBuilder sb = new StringBuilder();
+        sb.append("ERROR: ").append(header).append("\n");
+        sb.append("LINE: ").append(errorLine);
+        detailedMessage = sb.toString();
+      }
+    }
+
+    return detailedMessage;
+  }
+
+  public String getMessageHeader(){
+    return this.header;
+  }
+
+  private String getDetailedMessageWithLocation() {
+    StringBuilder sb = new StringBuilder();
+    int displayLimit = 80;
+    String queryPrefix = "LINE " + line + ":" + charPositionInLine + " ";
+    String prefixPadding = StringUtils.repeat(" ", queryPrefix.length());
+    String locationString;
+
+    int tokenLength = offendingToken.getStopIndex() - offendingToken.getStartIndex() + 1;
+    if(tokenLength > 0){
+      locationString = StringUtils.repeat(" ", charPositionInLine) + StringUtils.repeat("^", tokenLength);
+    } else {
+      locationString = StringUtils.repeat(" ", charPositionInLine) + "^";
+    }
+
+    sb.append("ERROR: ").append(header).append("\n");
+    sb.append(queryPrefix);
+
+    if (errorLine.length() > displayLimit) {
+      int padding = (displayLimit / 2);
+
+      String ellipsis = " ... ";
+      int startPos = locationString.length() - padding - 1;
+      if (startPos <= 0) {
+        startPos = 0;
+        sb.append(errorLine.substring(startPos, displayLimit)).append(ellipsis).append("\n");
+        sb.append(prefixPadding).append(locationString);
+      } else if (errorLine.length() - (locationString.length() + padding) <= 0) {
+        startPos = errorLine.length() - displayLimit - 1;
+        sb.append(ellipsis).append(errorLine.substring(startPos)).append("\n");
+        sb.append(prefixPadding).append(StringUtils.repeat(" ", ellipsis.length()))
+            .append(locationString.substring(startPos));
+      } else {
+        sb.append(ellipsis).append(errorLine.substring(startPos, startPos + displayLimit)).append(ellipsis).append("\n");
+        sb.append(prefixPadding).append(StringUtils.repeat(" ", ellipsis.length()))
+            .append(locationString.substring(startPos));
+      }
+    } else {
+      sb.append(errorLine).append("\n");
+      sb.append(prefixPadding).append(locationString);
+    }
+    return sb.toString();
+  }
+}

http://git-wip-us.apache.org/repos/asf/tajo/blob/33b8893f/tajo-project/pom.xml
----------------------------------------------------------------------
diff --git a/tajo-project/pom.xml b/tajo-project/pom.xml
index 7a5ed66..4978f75 100644
--- a/tajo-project/pom.xml
+++ b/tajo-project/pom.xml
@@ -781,6 +781,11 @@
       </dependency>
       <dependency>
         <groupId>org.apache.tajo</groupId>
+        <artifactId>tajo-sql-parser</artifactId>
+        <version>${tajo.version}</version>
+      </dependency>
+      <dependency>
+        <groupId>org.apache.tajo</groupId>
         <artifactId>tajo-pullserver</artifactId>
         <version>${tajo.version}</version>
       </dependency>