layout: global title: PIVOT Clause displayTitle: PIVOT 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 PIVOT
clause is used for data perspective. We can get the aggregated values based on specific column values, which will be turned to multiple columns used in SELECT
clause. The PIVOT
clause can be specified after the table name or subquery.
PIVOT ( { aggregate_expression [ AS aggregate_expression_alias ] } [ , ... ] FOR column_list IN ( expression_list ) )
aggregate_expression
Specifies an aggregate expression (SUM(a), COUNT(DISTINCT b), etc.).
aggregate_expression_alias
Specifies an alias for the aggregate expression.
column_list
Contains columns in the FROM
clause, which specifies the columns we want to replace with new columns. We can use brackets to surround the columns, such as (c1, c2)
.
expression_list
Specifies new columns, which are used to match values in column_list
as the aggregating condition. We can also add aliases for them.
CREATE TABLE person (id INT, name STRING, age INT, class INT, address STRING); INSERT INTO person VALUES (100, 'John', 30, 1, 'Street 1'), (200, 'Mary', NULL, 1, 'Street 2'), (300, 'Mike', 80, 3, 'Street 3'), (400, 'Dan', 50, 4, 'Street 4'); SELECT * FROM person PIVOT ( SUM(age) AS a, AVG(class) AS c FOR name IN ('John' AS john, 'Mike' AS mike) ); +------+-----------+---------+---------+---------+---------+ | id | address | john_a | john_c | mike_a | mike_c | +------+-----------+---------+---------+---------+---------+ | 200 | Street 2 | NULL | NULL | NULL | NULL | | 100 | Street 1 | 30 | 1.0 | NULL | NULL | | 300 | Street 3 | NULL | NULL | 80 | 3.0 | | 400 | Street 4 | NULL | NULL | NULL | NULL | +------+-----------+---------+---------+---------+---------+ SELECT * FROM person PIVOT ( SUM(age) AS a, AVG(class) AS c FOR (name, age) IN (('John', 30) AS c1, ('Mike', 40) AS c2) ); +------+-----------+-------+-------+-------+-------+ | id | address | c1_a | c1_c | c2_a | c2_c | +------+-----------+-------+-------+-------+-------+ | 200 | Street 2 | NULL | NULL | NULL | NULL | | 100 | Street 1 | 30 | 1.0 | NULL | NULL | | 300 | Street 3 | NULL | NULL | NULL | NULL | | 400 | Street 4 | NULL | NULL | NULL | NULL | +------+-----------+-------+-------+-------+-------+