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mergebot-role pushed a commit to branch asf-site
in repository https://gitbox.apache.org/repos/asf/beam-site.git
commit 6386ac2149c4320f0891c33b545bbf5b0bc8287a
Author: Mergebot <merge...@apache.org>
AuthorDate: Sat Aug 26 04:38:02 2017 +0000
Prepare repository for deployment.
---
content/documentation/dsls/sql/index.html | 73 +++++++++++++++++++++++++------
1 file changed, 59 insertions(+), 14 deletions(-)
diff --git a/content/documentation/dsls/sql/index.html
b/content/documentation/dsls/sql/index.html
index af40420..dc501b5 100644
--- a/content/documentation/dsls/sql/index.html
+++ b/content/documentation/dsls/sql/index.html
@@ -266,18 +266,65 @@ PCollection<BeamRecord> output =
namesAndFoods.apply(
<p><a
href="https://github.com/apache/beam/blob/DSL_SQL/sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/example/BeamSqlExample.java";>BeamSqlExample</a>
in the code repository shows basic usage of both APIs.</p>
<h1 id="a-namefunctionalitya3-functionality-in-beam-sql"><a
name="functionality"></a>3. Functionality in Beam SQL</h1>
-<p>Just as the unified model for both bounded and unbounded data in Beam, SQL
DSL provides the same functionalities for bounded and unbounded <code
class="highlighter-rouge">PCollection</code> as well.</p>
+<p>Just as the unified model for both bounded and unbounded data in Beam, SQL
DSL provides the same functionalities for bounded and unbounded <code
class="highlighter-rouge">PCollection</code> as well. Here’s the supported SQL
grammar supported in <a
href="http://en.wikipedia.org/wiki/Backus%E2%80%93Naur_Form";>BNF</a>-like form.
An <code class="highlighter-rouge">UnsupportedOperationException</code> is
thrown for unsupported features.</p>
+
+<div class="highlighter-rouge"><pre class="highlight"><code>query:
+ {
+ select
+ | query UNION [ ALL ] query
+ | query MINUS [ ALL ] query
+ | query INTERSECT [ ALL ] query
+ }
+ [ ORDER BY orderItem [, orderItem ]* LIMIT count [OFFSET offset] ]
+
+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 ]* ')'
-<p>Note that, SQL support is not fully completed. Queries that include
unsupported features would cause an <code
class="highlighter-rouge">UnsupportedOperationException</code>.</p>
+</code></pre>
+</div>
<h2 id="a-namefeaturesa31-supported-features"><a name="features"></a>3.1.
Supported Features</h2>
-<p>The following features are supported in current repository:</p>
-
-<p><strong>1. filter clauses;</strong></p>
-<p><strong>2. data field projections;</strong></p>
-
-<p><strong>3. aggregations;</strong></p>
+<p><strong>1. aggregations;</strong></p>
<p>Beam SQL supports aggregation functions with group_by in global_window,
fixed_window, sliding_window and session_window. A field with type <code
class="highlighter-rouge">TIMESTAMP</code> is required to specify
fixed_window/sliding_window/session_window. The field is used as event
timestamp for rows. See below for several examples:</p>
@@ -305,7 +352,7 @@ SELECT f_int, COUNT(*) AS `size` FROM PCOLLECTION GROUP BY
f_int, SESSION(f_time
</code></pre>
</div>
-<p><strong>4. Join (inner, left_outer, right_outer);</strong></p>
+<p><strong>2. Join (inner, left_outer, right_outer);</strong></p>
<p>The scenarios of join can be categorized into 3 cases:</p>
@@ -324,9 +371,7 @@ SELECT f_int, COUNT(*) AS `size` FROM PCOLLECTION GROUP BY
f_int, SESSION(f_time
<li>window/trigger is inherented from upstreams, which should be
consistent;</li>
</ul>
-<p><strong>5. built-in SQL functions</strong></p>
-
-<p><strong>6. User Defined Function (UDF) and User Defined Aggregate Function
(UDAF);</strong></p>
+<p><strong>3. User Defined Function (UDF) and User Defined Aggregate Function
(UDAF);</strong></p>
<p>If the required function is not available, developers can register their
own UDF(for scalar function) and UDAF(for aggregation function).</p>
@@ -405,7 +450,7 @@ PCollection<BeamSqlRow> result =
</code></pre>
</div>
-<h2 id="a-namedata-typea33-data-types"><a name="data-type"></a>3.3. Data
Types</h2>
+<h2 id="a-namedata-typea32-data-types"><a name="data-type"></a>3.2. Data
Types</h2>
<p>Each type in Beam SQL maps to a Java class to holds the value in <code
class="highlighter-rouge">BeamRecord</code>. The following table lists the
relation between SQL types and Java classes, which are supported in current
repository:</p>
<table class="table">
@@ -455,7 +500,7 @@ PCollection<BeamSqlRow> result =
</tbody>
</table>
-<h2 id="a-namebuilt-in-functionsa34-built-in-sql-functions"><a
name="built-in-functions"></a>3.4. built-in SQL functions</h2>
+<h2 id="a-namebuilt-in-functionsa33-built-in-sql-functions"><a
name="built-in-functions"></a>3.3. built-in SQL functions</h2>
<p>Beam SQL has implemented lots of build-in functions defined in <a
href="http://calcite.apache.org";>Apache Calcite</a>. The available functions
are listed as below:</p>
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