Computes the average, for a set of rows, of a numeric expression or of a set unique values.
AVG( numeric-expression | DISTINCT numeric-expression )
AVG( numeric-expression ) OVER ( window-spec )
window-spec : see Syntax 2 instructions in the Usage section below
numeric-expression The expression whose average is calculated over a set of rows.
DISTINCT numeric-expression Computes the average of the unique numeric values in the input.
This average does not include rows where the numeric-expression is the NULL value. Returns the NULL value for a group containing no rows.
Syntax 2 represents usage as a window function in a SELECT statement. As such, elements of window-spec can be specified either in the function syntax (inline), or in conjunction with a WINDOW clause in the SELECT statement. See the window-spec definition provided in WINDOW clause.
For more information about using window functions in SELECT statements, including working examples, see Window functions.
SQL/2003 Core feature. Syntax 2 is feature T611.
The following statement returns the value 49988.623200.
SELECT AVG( Salary ) FROM Employees ;
The following statement could be used to determine the average based on unique prices in the production list:
SELECT AVG( DISTINCT ListPrice ) FROM Production ;