Returns the total of the specified expression for each group of rows.
SUM( expression | DISTINCT expression )
SUM( expression ) OVER ( window-spec )
window-spec : see Syntax 2 instructions in the Usage section below
expression The object to be summed. This is commonly a column name.
DISTINCT expression Computes the sum of the unique values of expression in the input.
Rows where the specified expression is NULL are not included.
Returns NULL 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 T611.
The following statement returns the value 3749146.740.
SELECT SUM( Salary ) FROM Employees;