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? ![image](https://user-images.githubusercontent.com/46367746/88148830-c6dc1f80-cc31-11ea-81ea-13bc9dc34550.png) ![image](https://user-images.githubusercontent.com/46367746/88148968-fb4fdb80-cc31-11ea-8649-e8297cf5813e.png) ![image](https://user-images.githubusercontent.com/46367746/88149000-073b9d80-cc32-11ea-9aa4-f914ecd72663.png) ![image](https://user-images.githubusercontent.com/46367746/88149021-0f93d880-cc32-11ea-86ed-7db8672b5aac.png) ### 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>
149 lines
4.3 KiB
Markdown
149 lines
4.3 KiB
Markdown
---
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layout: global
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title: ORDER BY Clause
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displayTitle: ORDER 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 `ORDER BY` clause is used to return the result rows in a sorted manner
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in the user specified order. Unlike the [SORT BY](sql-ref-syntax-qry-select-sortby.html)
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clause, this clause guarantees a total order in the output.
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### Syntax
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```sql
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ORDER BY { expression [ sort_direction | nulls_sort_oder ] [ , ... ] }
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```
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### Parameters
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* **ORDER BY**
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Specifies a comma-separated list of expressions along with optional parameters `sort_direction`
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and `nulls_sort_order` which are used to sort the rows.
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* **sort_direction**
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Optionally specifies whether to sort the rows in ascending or descending
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order. The valid values for the sort direction are `ASC` for ascending
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and `DESC` for descending. If sort direction is not explicitly specified, then by default
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rows are sorted ascending.
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**Syntax:** [ ASC `|` DESC ]
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* **nulls_sort_order**
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Optionally specifies whether NULL values are returned before/after non-NULL values. If
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`null_sort_order` is not specified, then NULLs sort first if sort order is
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`ASC` and NULLS sort last if sort order is `DESC`.
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1. If `NULLS FIRST` is specified, then NULL values are returned first
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regardless of the sort order.
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2. If `NULLS LAST` is specified, then NULL values are returned last regardless of
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the sort order.
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**Syntax:** `[ NULLS { FIRST | LAST } ]`
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### Examples
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```sql
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CREATE TABLE person (id INT, name STRING, age INT);
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INSERT INTO person VALUES
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(100, 'John', 30),
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(200, 'Mary', NULL),
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(300, 'Mike', 80),
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(400, 'Jerry', NULL),
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(500, 'Dan', 50);
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-- Sort rows by age. By default rows are sorted in ascending manner with NULL FIRST.
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SELECT name, age FROM person ORDER BY age;
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+-----+----+
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| name| age|
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+-----+----+
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|Jerry|null|
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| Mary|null|
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| John| 30|
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| Dan| 50|
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| Mike| 80|
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+-----+----+
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-- Sort rows in ascending manner keeping null values to be last.
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SELECT name, age FROM person ORDER BY age NULLS LAST;
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+-----+----+
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| name| age|
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+-----+----+
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| John| 30|
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| Dan| 50|
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| Mike| 80|
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| Mary|null|
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|Jerry|null|
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+-----+----+
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-- Sort rows by age in descending manner, which defaults to NULL LAST.
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SELECT name, age FROM person ORDER BY age DESC;
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+-----+----+
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| name| age|
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+-----+----+
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| Mike| 80|
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| Dan| 50|
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| John| 30|
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|Jerry|null|
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| Mary|null|
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+-----+----+
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-- Sort rows in ascending manner keeping null values to be first.
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SELECT name, age FROM person ORDER BY age DESC NULLS FIRST;
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+-----+----+
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| name| age|
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+-----+----+
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|Jerry|null|
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| Mary|null|
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| Mike| 80|
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| Dan| 50|
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| John| 30|
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+-----+----+
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-- Sort rows based on more than one column with each column having different
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-- sort direction.
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SELECT * FROM person ORDER BY name ASC, age DESC;
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+---+-----+----+
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| id| name| age|
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+---+-----+----+
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|500| Dan| 50|
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|400|Jerry|null|
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|100| John| 30|
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|200| Mary|null|
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|300| Mike| 80|
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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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* [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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* [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)
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