layout: global title: SELECT displayTitle: WHERE clause license: | 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
The WHERE
clause is used to limit the results of the FROM
clause of a query or a subquery based on the specified condition.
WHERE boolean_expression
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
).
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| +---+----+----+