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Posted to commits@beam.apache.org by me...@apache.org on 2017/08/26 00:05:50 UTC
[beam-site] branch mergebot updated (a9b328b -> db3f3b9)
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from a9b328b This closes #303
add dbb8f55 Prepare repository for deployment.
new ba868d8 add SQL grammar in BNF
new f5c30d6 correct the syntax of ORDER_BY LIMIT
new db3f3b9 This closes #300
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Summary of changes:
content/documentation/io/built-in/index.html | 2 +
src/documentation/dsls/sql.md | 73 ++++++++++++++++++++++------
2 files changed, 61 insertions(+), 14 deletions(-)
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[beam-site] 03/03: This closes #300
Posted by me...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
mergebot-role pushed a commit to branch mergebot
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commit db3f3b9f378e6d240d8c22cbae161862aefb0a77
Merge: dbb8f55 f5c30d6
Author: Mergebot <me...@apache.org>
AuthorDate: Sat Aug 26 00:05:24 2017 +0000
This closes #300
src/documentation/dsls/sql.md | 73 ++++++++++++++++++++++++++++++++++---------
1 file changed, 59 insertions(+), 14 deletions(-)
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[beam-site] 02/03: correct the syntax of ORDER_BY LIMIT
Posted by me...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
mergebot-role pushed a commit to branch mergebot
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commit f5c30d695f25952f80f1b5c8921aeafa24c9f9a6
Author: mingmxu <mi...@ebay.com>
AuthorDate: Fri Aug 25 16:40:18 2017 -0700
correct the syntax of ORDER_BY LIMIT
---
src/documentation/dsls/sql.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/documentation/dsls/sql.md b/src/documentation/dsls/sql.md
index 5a7ad32..5c9308a 100644
--- a/src/documentation/dsls/sql.md
+++ b/src/documentation/dsls/sql.md
@@ -122,7 +122,7 @@ query:
| query MINUS [ ALL ] query
| query INTERSECT [ ALL ] query
}
- [ ORDER BY orderItem [, orderItem ]* LIMIT [offset] count ]
+ [ ORDER BY orderItem [, orderItem ]* LIMIT count [OFFSET offset] ]
orderItem:
expression [ ASC | DESC ]
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[beam-site] 01/03: add SQL grammar in BNF
Posted by me...@apache.org.
This is an automated email from the ASF dual-hosted git repository.
mergebot-role pushed a commit to branch mergebot
in repository https://gitbox.apache.org/repos/asf/beam-site.git
commit ba868d8af7cbb27e278e07c2f1cc12e3e7b55095
Author: mingmxu <mi...@ebay.com>
AuthorDate: Thu Aug 24 13:39:47 2017 -0700
add SQL grammar in BNF
---
src/documentation/dsls/sql.md | 73 ++++++++++++++++++++++++++++++++++---------
1 file changed, 59 insertions(+), 14 deletions(-)
diff --git a/src/documentation/dsls/sql.md b/src/documentation/dsls/sql.md
index ce893cd..5a7ad32 100644
--- a/src/documentation/dsls/sql.md
+++ b/src/documentation/dsls/sql.md
@@ -112,18 +112,65 @@ Both methods wrap the back-end details of parsing/validation/assembling, and del
[BeamSqlExample](https://github.com/apache/beam/blob/DSL_SQL/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/example/BeamSqlExample.java) in the code repository shows basic usage of both APIs.
# <a name="functionality"></a>3. Functionality in Beam SQL
-Just as the unified model for both bounded and unbounded data in Beam, SQL DSL provides the same functionalities for bounded and unbounded `PCollection` as well.
+Just as the unified model for both bounded and unbounded data in Beam, SQL DSL provides the same functionalities for bounded and unbounded `PCollection` as well. Here's the supported SQL grammar supported in [BNF](http://en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form)-like form. An `UnsupportedOperationException` is thrown for unsupported features.
-Note that, SQL support is not fully completed. Queries that include unsupported features would cause an `UnsupportedOperationException`.
-
-## <a name="features"></a>3.1. Supported Features
-The following features are supported in current repository:
+```
+query:
+ {
+ select
+ | query UNION [ ALL ] query
+ | query MINUS [ ALL ] query
+ | query INTERSECT [ ALL ] query
+ }
+ [ ORDER BY orderItem [, orderItem ]* LIMIT [offset] count ]
+
+orderItem:
+ expression [ ASC | DESC ]
+
+select:
+ SELECT
+ { * | projectItem [, projectItem ]* }
+ FROM tableExpression
+ [ WHERE booleanExpression ]
+ [ GROUP BY { groupItem [, groupItem ]* } ]
+ [ HAVING booleanExpression ]
+
+projectItem:
+ expression [ [ AS ] columnAlias ]
+ | tableAlias . *
+
+tableExpression:
+ tableReference [, tableReference ]*
+ | tableExpression [ ( LEFT | RIGHT ) [ OUTER ] ] JOIN tableExpression [ joinCondition ]
+
+booleanExpression:
+ expression [ IS NULL | IS NOT NULL ]
+ | expression [ > | >= | = | < | <= | <> ] expression
+ | booleanExpression [ AND | OR ] booleanExpression
+ | NOT booleanExpression
+ | '(' booleanExpression ')'
+
+joinCondition:
+ ON booleanExpression
+
+tableReference:
+ tableName [ [ AS ] alias ]
+
+values:
+ VALUES expression [, expression ]*
+
+groupItem:
+ expression
+ | '(' expression [, expression ]* ')'
+ | HOP '(' expression [, expression ]* ')'
+ | TUMBLE '(' expression [, expression ]* ')'
+ | SESSION '(' expression [, expression ]* ')'
-**1. filter clauses;**
+```
-**2. data field projections;**
+## <a name="features"></a>3.1. Supported Features
-**3. aggregations;**
+**1. aggregations;**
Beam SQL supports aggregation functions with group_by in global_window, fixed_window, sliding_window and session_window. A field with type `TIMESTAMP` is required to specify fixed_window/sliding_window/session_window. The field is used as event timestamp for rows. See below for several examples:
@@ -149,7 +196,7 @@ Repeatedly.forever(AfterWatermark.pastEndOfWindow().withLateFirings(AfterProcess
.pastFirstElementInPane().plusDelayOf(Duration.millis(delayTime.getTimeInMillis()))));
```
-**4. Join (inner, left_outer, right_outer);**
+**2. Join (inner, left_outer, right_outer);**
The scenarios of join can be categorized into 3 cases:
@@ -164,9 +211,7 @@ For case 1 and case 2, a standard join is utilized as long as the windowFn of th
* If it's a LEFT OUTER JOIN, the unbounded table should on the left side; If it's a RIGHT OUTER JOIN, the unbounded table should on the right side;
* window/trigger is inherented from upstreams, which should be consistent;
-**5. built-in SQL functions**
-
-**6. User Defined Function (UDF) and User Defined Aggregate Function (UDAF);**
+**3. User Defined Function (UDF) and User Defined Aggregate Function (UDAF);**
If the required function is not available, developers can register their own UDF(for scalar function) and UDAF(for aggregation function).
@@ -245,7 +290,7 @@ PCollection<BeamSqlRow> result =
BeamSql.simpleQuery(sql).withUdaf("squaresum", new SquareSum()));
```
-## <a name="data-type"></a>3.3. Data Types
+## <a name="data-type"></a>3.2. Data Types
Each type in Beam SQL maps to a Java class to holds the value in `BeamRecord`. The following table lists the relation between SQL types and Java classes, which are supported in current repository:
| SQL Type | Java class |
@@ -261,7 +306,7 @@ Each type in Beam SQL maps to a Java class to holds the value in `BeamRecord`. T
| Types.TIMESTAMP | java.util.Date |
{:.table}
-## <a name="built-in-functions"></a>3.4. built-in SQL functions
+## <a name="built-in-functions"></a>3.3. built-in SQL functions
Beam SQL has implemented lots of build-in functions defined in [Apache Calcite](http://calcite.apache.org). The available functions are listed as below:
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