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>
126 lines
5 KiB
Markdown
126 lines
5 KiB
Markdown
---
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layout: global
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title: LATERAL VIEW Clause
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displayTitle: LATERAL VIEW 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 `LATERAL VIEW` clause is used in conjunction with generator functions such as `EXPLODE`, which will generate a virtual table containing one or more rows. `LATERAL VIEW` will apply the rows to each original output row.
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### Syntax
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```sql
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LATERAL VIEW [ OUTER ] generator_function ( expression [ , ... ] ) [ table_alias ] AS column_alias [ , ... ]
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```
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### Parameters
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* **OUTER**
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If `OUTER` specified, returns null if an input array/map is empty or null.
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* **generator_function**
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Specifies a generator function (EXPLODE, INLINE, etc.).
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* **table_alias**
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The alias for `generator_function`, which is optional.
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* **column_alias**
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Lists the column aliases of `generator_function`, which may be used in output rows. We may have multiple aliases if `generator_function` have multiple output columns.
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### Examples
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```sql
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CREATE TABLE person (id INT, name STRING, age INT, class INT, address STRING);
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INSERT INTO person VALUES
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(100, 'John', 30, 1, 'Street 1'),
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(200, 'Mary', NULL, 1, 'Street 2'),
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(300, 'Mike', 80, 3, 'Street 3'),
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(400, 'Dan', 50, 4, 'Street 4');
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SELECT * FROM person
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LATERAL VIEW EXPLODE(ARRAY(30, 60)) tabelName AS c_age
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LATERAL VIEW EXPLODE(ARRAY(40, 80)) AS d_age;
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+------+-------+-------+--------+-----------+--------+--------+
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| id | name | age | class | address | c_age | d_age |
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+------+-------+-------+--------+-----------+--------+--------+
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| 100 | John | 30 | 1 | Street 1 | 30 | 40 |
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| 100 | John | 30 | 1 | Street 1 | 30 | 80 |
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| 100 | John | 30 | 1 | Street 1 | 60 | 40 |
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| 100 | John | 30 | 1 | Street 1 | 60 | 80 |
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| 200 | Mary | NULL | 1 | Street 2 | 30 | 40 |
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| 200 | Mary | NULL | 1 | Street 2 | 30 | 80 |
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| 200 | Mary | NULL | 1 | Street 2 | 60 | 40 |
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| 200 | Mary | NULL | 1 | Street 2 | 60 | 80 |
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| 300 | Mike | 80 | 3 | Street 3 | 30 | 40 |
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| 300 | Mike | 80 | 3 | Street 3 | 30 | 80 |
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| 300 | Mike | 80 | 3 | Street 3 | 60 | 40 |
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| 300 | Mike | 80 | 3 | Street 3 | 60 | 80 |
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| 400 | Dan | 50 | 4 | Street 4 | 30 | 40 |
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| 400 | Dan | 50 | 4 | Street 4 | 30 | 80 |
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| 400 | Dan | 50 | 4 | Street 4 | 60 | 40 |
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| 400 | Dan | 50 | 4 | Street 4 | 60 | 80 |
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+------+-------+-------+--------+-----------+--------+--------+
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SELECT c_age, COUNT(1) FROM person
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LATERAL VIEW EXPLODE(ARRAY(30, 60)) AS c_age
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LATERAL VIEW EXPLODE(ARRAY(40, 80)) AS d_age
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GROUP BY c_age;
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+--------+-----------+
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| c_age | count(1) |
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+--------+-----------+
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| 60 | 8 |
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| 30 | 8 |
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+--------+-----------+
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SELECT * FROM person
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LATERAL VIEW EXPLODE(ARRAY()) tabelName AS c_age;
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+-----+-------+------+--------+----------+--------+
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| id | name | age | class | address | c_age |
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+-----+-------+------+--------+----------+--------+
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+-----+-------+------+--------+----------+--------+
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SELECT * FROM person
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LATERAL VIEW OUTER EXPLODE(ARRAY()) tabelName AS c_age;
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+------+-------+-------+--------+-----------+--------+
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| id | name | age | class | address | c_age |
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+------+-------+-------+--------+-----------+--------+
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| 100 | John | 30 | 1 | Street 1 | NULL |
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| 200 | Mary | NULL | 1 | Street 2 | NULL |
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| 300 | Mike | 80 | 3 | Street 3 | NULL |
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| 400 | Dan | 50 | 4 | Street 4 | NULL |
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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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* [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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