[jira] [Comment Edited] (CALCITE-3226) RelBuilder doesn't keep the alias when scan from an expanded view

["Ruben Quesada Lopez (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-3226?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16903242#comment-16903242 ] 

Ruben Quesada Lopez edited comment on CALCITE-3226 at 8/8/19 7:08 PM:
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Sorry, [~julianhyde]. As described by [~jinxing6042@126.com], it seems it is not possible to get to that scenario, because the view always produces a {{Project+Scan}}, even in case of a simple {{“select * from t”}}.


was (Author: rubenql):
Sorry, [~julianhyde]. As described by [~jinxing6042@126.com], it seems it is not possible to get to that scenario, because the view always produce a {{Project+Scan}}, even in case of a simple {{“select * from t”}}.

> RelBuilder doesn't keep the alias when scan from an expanded view
> -----------------------------------------------------------------
>
>                 Key: CALCITE-3226
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3226
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>            Reporter: jin xing
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 1.21.0
>
>          Time Spent: 1h 20m
>  Remaining Estimate: 0h
>
> In current implementation of {{RelBuilder::scan}} ([https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/tools/RelBuilder.java#L1048]), the alias can be derived and recorded into {{Frame}} only when the {{RelNode}} is a {{TableScan}} ([https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/tools/RelBuilder.java#L2754]).
>  But when {{RelBuilder::scan}} from an expanded view, the node is not a {{TableScan}} and the alias is not kept.  Below test failed - we cannot reference a field by alias "MYVIEW".
> {code:java}
>   @Test public void testExpandViewShouldKeepAlias() throws SQLException {
>     try (Connection connection = DriverManager.getConnection("jdbc:calcite:")) {
>       final Frameworks.ConfigBuilder configBuilder =
>           expandingConfig(connection);
>       final RelOptTable.ViewExpander viewExpander =
>           (RelOptTable.ViewExpander) Frameworks.getPlanner(configBuilder.build());
>       final RelFactories.TableScanFactory tableScanFactory =
>           RelFactories.expandingScanFactory(viewExpander,
>               RelFactories.DEFAULT_TABLE_SCAN_FACTORY);
>       configBuilder.context(Contexts.of(tableScanFactory));
>       final RelBuilder builder = RelBuilder.create(configBuilder.build());
>       RelNode node =
>           builder.scan("MYVIEW")
>               .project(
>                   builder.field(1, "MYVIEW", "EMPNO"),           // Exception thrown from here.
>                   builder.field(1, "MYVIEW", "ENAME"))
>               .build();
>       String expected =
>           "LogicalProject(EMPNO=[$0], ENAME=[$1])\n"
>               + "  LogicalFilter(condition=[=(1, 1)])\n"
>                   + "    LogicalTableScan(table=[[scott, EMP]])\n";
>       assertThat(node, hasTree(expected));
>     }
>   }
> {code}



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