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>
110 lines
3.1 KiB
Markdown
110 lines
3.1 KiB
Markdown
---
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layout: global
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title: LIMIT Clause
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displayTitle: LIMIT 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 `LIMIT` clause is used to constrain the number of rows returned by
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the [SELECT](sql-ref-syntax-qry-select.html) statement. In general, this clause
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is used in conjunction with [ORDER BY](sql-ref-syntax-qry-select-orderby.html) to
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ensure that the results are deterministic.
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### Syntax
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```sql
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LIMIT { ALL | integer_expression }
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```
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### Parameters
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* **ALL**
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If specified, the query returns all the rows. In other words, no limit is applied if this
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option is specified.
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* **integer_expression**
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Specifies a foldable expression that returns an integer.
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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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-- Select the first two rows.
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SELECT name, age FROM person ORDER BY name LIMIT 2;
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+------+---+
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| name|age|
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+------+---+
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|Anil B| 18|
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|Jack N| 16|
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+------+---+
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-- Specifying ALL option on LIMIT returns all the rows.
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SELECT name, age FROM person ORDER BY name LIMIT ALL;
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+-------+---+
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| name|age|
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+-------+---+
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| Anil B| 18|
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| Jack N| 16|
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| John A| 18|
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| Mike A| 25|
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|Shone S| 16|
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|Zen Hui| 25|
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+-------+---+
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-- A function expression as an input to LIMIT.
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SELECT name, age FROM person ORDER BY name LIMIT length('SPARK');
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+-------+---+
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| name|age|
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+-------+---+
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| Anil B| 18|
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| Jack N| 16|
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| John A| 18|
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| Mike A| 25|
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|Shone S| 16|
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+-------+---+
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-- A non-foldable expression as an input to LIMIT is not allowed.
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SELECT name, age FROM person ORDER BY name LIMIT length(name);
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org.apache.spark.sql.AnalysisException: The limit expression must evaluate to a constant value ...
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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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* [DISTRIBUTE BY Clause](sql-ref-syntax-qry-select-distribute-by.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)
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