SQL - SUM

The SUM aggregate function allows selecting the total for a numeric column.

The SUM syntax is displayed below:

SELECT SUM(Column1) FROM Table1

We are going to use the Sales table to illustrate the use of SUM clause:

Sales:

CustomerID	Date	SaleAmount
2	5/6/2004	$100.22
1	5/7/2004	$99.95
3	5/7/2004	$122.95
3	5/13/2004	$100.00
4	5/22/2004	$555.55

Consider the following SUM statement:

SELECT SUM(SaleAmount) FROM Sales

This SQL statement will return the sum of all SaleAmount fields and the result of it will be:

SaleAmount

$978.67

Of course you can specify search criteria using the WHERE clause in your SUM statement. If you want to select the total sales for customer with CustomerID = 3, you will use the following SUM statement:

SELECT SUM(SaleAmount) FROM Sales WHERE CustomerID = 3

The result will be:

SaleAmount

$222.95