Purpose

Specifies the names of one or more columns by which the returned values are grouped. This clause is used to return a set of aggregate values.

Syntax

GROUP BY column_expression [,...]

where:

column_expression
is either a column name or a SQL expression. Multiple values must be separated by a comma. If column_expression is a column name, it must match one of the column names specified in the Select clause. Also, the Group By clause must include all non-aggregate columns specified in the Select list.

Example

The following example totals the salaries in each department:

SELECT dept_id, sum(salary) FROM emp GROUP BY dept_id

This statement returns one row for each distinct department ID. Each row contains the department ID and the sum of the salaries of the employees in the department.

See also

Subqueries

SQL expressions