Computes the average of a collection of values. The keyword DISTINCT specifies that the duplicate values are to be eliminated before computing the average.

Syntax

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

Notes

  • 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

This example illustrates the AVG function:

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