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

Rows where the specified expression is NULL are not included.

Returns NULL for a group containing no rows.

The following statement returns the value 3749146.740:

SELECT SUM( salary )
FROM Employees