Description

The SUM( ) function returns the sum of expr. It returns NULL if the set has no matching rows.

This function has the form:

SELECT SUM([DISTINCT] expr)

Parameter	Description
expr	An expression

Return Value

Returns the sum of expr. If the return set has no rows, SUM() returns NULL. The DISTINCT keyword can be used in MySQL 5.5 to sum only the distinct values of expr.

Examples

The following example shows the basic use of this function:

ID	Name	Class	Score
1	John Deo	Four	75
2	Max Ruin	Three	85
3	Arnold	Three	55
4	Krish Star	Four	60
5	John Mike	Four	60
6	Alex John	Four	55

Apply the SUM() function to the 'score' column:

SELECT sum(score) FROM 'student'
+-------------------------+
| SUM(score)              |
+-------------------------+
| 390                     |
+-------------------------+
1 row in set (0.00 sec)