SUM Function [Aggregate]

Returns the total of the specified expression for each group of rows.

Syntax

SUM ( expression | DISTINCT column-name )

Parameter	Description
expression	The object to be summed. This is commonly a column name.
DISTINCT column-name	Computes the sum of the unique values in `column-name` for each group of rows. This is of limited usefulness, but is included for completeness.

INTEGER

DOUBLE

NUMERIC

The following statement returns the value 3749146.740:

SELECT SUM( salary )
FROM Employees

Rows where the specified expression is NULL are not included.

Returns NULL for a group containing no rows.