8de43338be
### What changes were proposed in this pull request? update sql-ref docs, the following key words will be added in this PR. CASE/ELSE WHEN/THEN MAP KEYS TERMINATED BY NULL DEFINED AS LINES TERMINATED BY ESCAPED BY COLLECTION ITEMS TERMINATED BY PIVOT LATERAL VIEW OUTER? ROW FORMAT SERDE ROW FORMAT DELIMITED FIELDS TERMINATED BY IGNORE NULLS FIRST LAST ### Why are the changes needed? let more users know the sql key words usage ### Does this PR introduce _any_ user-facing change?     ### How was this patch tested? No Closes #29056 from GuoPhilipse/add-missing-keywords. Lead-authored-by: GuoPhilipse <guofei_ok@126.com> Co-authored-by: GuoPhilipse <46367746+GuoPhilipse@users.noreply.github.com> Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
99 lines
3.1 KiB
Markdown
99 lines
3.1 KiB
Markdown
---
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layout: global
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title: DISTRIBUTE BY Clause
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displayTitle: DISTRIBUTE BY Clause
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license: |
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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---
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### Description
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The `DISTRIBUTE BY` clause is used to repartition the data based
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on the input expressions. Unlike the [CLUSTER BY](sql-ref-syntax-qry-select-clusterby.html)
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clause, this does not sort the data within each partition.
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### Syntax
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```sql
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DISTRIBUTE BY { expression [ , ... ] }
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```
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### Parameters
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* **expression**
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Specifies combination of one or more values, operators and SQL functions that results in a value.
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### Examples
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```sql
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CREATE TABLE person (name STRING, age INT);
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INSERT INTO person VALUES
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('Zen Hui', 25),
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('Anil B', 18),
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('Shone S', 16),
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('Mike A', 25),
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('John A', 18),
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('Jack N', 16);
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-- Reduce the number of shuffle partitions to 2 to illustrate the behavior of `DISTRIBUTE BY`.
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-- It's easier to see the clustering and sorting behavior with less number of partitions.
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SET spark.sql.shuffle.partitions = 2;
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-- Select the rows with no ordering. Please note that without any sort directive, the result
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-- of the query is not deterministic. It's included here to just contrast it with the
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-- behavior of `DISTRIBUTE BY`. The query below produces rows where age columns are not
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-- clustered together.
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SELECT age, name FROM person;
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+---+-------+
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|age| name|
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+---+-------+
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| 16|Shone S|
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| 25|Zen Hui|
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| 16| Jack N|
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| 25| Mike A|
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| 18| John A|
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| 18| Anil B|
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+---+-------+
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-- Produces rows clustered by age. Persons with same age are clustered together.
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-- Unlike `CLUSTER BY` clause, the rows are not sorted within a partition.
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SELECT age, name FROM person DISTRIBUTE BY age;
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+---+-------+
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|age| name|
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+---+-------+
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| 25|Zen Hui|
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| 25| Mike A|
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| 18| John A|
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| 18| Anil B|
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| 16|Shone S|
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| 16| Jack N|
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+---+-------+
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```
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### Related Statements
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* [SELECT Main](sql-ref-syntax-qry-select.html)
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* [WHERE Clause](sql-ref-syntax-qry-select-where.html)
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* [GROUP BY Clause](sql-ref-syntax-qry-select-groupby.html)
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* [HAVING Clause](sql-ref-syntax-qry-select-having.html)
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* [ORDER BY Clause](sql-ref-syntax-qry-select-orderby.html)
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* [SORT BY Clause](sql-ref-syntax-qry-select-sortby.html)
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* [CLUSTER BY Clause](sql-ref-syntax-qry-select-clusterby.html)
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* [LIMIT Clause](sql-ref-syntax-qry-select-limit.html)
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* [CASE Clause](sql-ref-syntax-qry-select-case.html)
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* [PIVOT Clause](sql-ref-syntax-qry-select-pivot.html)
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* [LATERAL VIEW Clause](sql-ref-syntax-qry-select-lateral-view.html) |