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### 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>
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| layout | title | displayTitle | license |
|---|---|---|---|
| global | SELECT | WHERE clause | Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. |
Description
The WHERE clause is used to limit the results of the FROM
clause of a query or a subquery based on the specified condition.
Syntax
WHERE boolean_expression
Parameters
-
boolean_expression
Specifies any expression that evaluates to a result type
boolean. Two or more expressions may be combined together using the logical operators (AND,OR).
Examples
CREATE TABLE person (id INT, name STRING, age INT);
INSERT INTO person VALUES
(100, 'John', 30),
(200, 'Mary', NULL),
(300, 'Mike', 80),
(400, 'Dan', 50);
-- Comparison operator in `WHERE` clause.
SELECT * FROM person WHERE id > 200 ORDER BY id;
+---+----+---+
| id|name|age|
+---+----+---+
|300|Mike| 80|
|400| Dan| 50|
+---+----+---+
-- Comparison and logical operators in `WHERE` clause.
SELECT * FROM person WHERE id = 200 OR id = 300 ORDER BY id;
+---+----+----+
| id|name| age|
+---+----+----+
|200|Mary|null|
|300|Mike| 80|
+---+----+----+
-- IS NULL expression in `WHERE` clause.
SELECT * FROM person WHERE id > 300 OR age IS NULL ORDER BY id;
+---+----+----+
| id|name| age|
+---+----+----+
|200|Mary|null|
|400| Dan| 50|
+---+----+----+
-- Function expression in `WHERE` clause.
SELECT * FROM person WHERE length(name) > 3 ORDER BY id;
+---+----+----+
| id|name| age|
+---+----+----+
|100|John| 30|
|200|Mary|null|
|300|Mike| 80|
+---+----+----+
-- `BETWEEN` expression in `WHERE` clause.
SELECT * FROM person WHERE id BETWEEN 200 AND 300 ORDER BY id;
+---+----+----+
| id|name| age|
+---+----+----+
|200|Mary|null|
|300|Mike| 80|
+---+----+----+
-- Scalar Subquery in `WHERE` clause.
SELECT * FROM person WHERE age > (SELECT avg(age) FROM person);
+---+----+---+
| id|name|age|
+---+----+---+
|300|Mike| 80|
+---+----+---+
-- Correlated Subquery in `WHERE` clause.
SELECT * FROM person AS parent
WHERE EXISTS (
SELECT 1 FROM person AS child
WHERE parent.id = child.id AND child.age IS NULL
);
+---+----+----+
|id |name|age |
+---+----+----+
|200|Mary|null|
+---+----+----+