4.9.1.1 AVG

Syntax

AVG ( { [ALL] expression } | { DISTINCT column_ref } )

Description

The aggregate function AVG computes the average of a collection of values. The keyword DISTINCT specifies that the duplicate values are to be eliminated before computing the average.

• Null values are eliminated before the average value is computed. If all the values are null, the result is null.
• The argument to the function must be of type SMALLINT, INTEGER, NUMERIC, REAL or FLOAT.
• The result is of type NUMERIC.

Example

SELECT AVG (salary)
    FROM employee
    WHERE deptno = 20 ;