SQL GROUP BY Statement

Aggregate functions often need an added GROUP BY statement.

The GROUP BY statement is used in conjunction with the aggregate functions to group the result-set by one or more columns.

SQL GROUP BY Syntax

SELECT column_name, aggregate_function(column_name) FROM table_name WHERE column_name operator value GROUP BY column_name

SQL GROUP BY Example

We have the following "Orders" table:

Id	OrderDate	OrderPrice	Customer
1	2008/11/12	1000	Navis
2	2008/10/23	1600	Nilsen
3	2008/09/02	700	Navis
4	2008/09/03	300	Navis
5	2008/08/30	2000	Jensen
6	2008/10/04	100	Nilsen

Now we want to find the total sum (total order) of each customer.
We will have to use the GROUP BY statement to group the customers.

We use the following SQL statement:

SELECT Customer,SUM(OrderPrice) FROM Orders GROUP BY Customer

The result-set will look like this:

Customer	SUM(OrderPrice)
Navis	2000
Nilsen	1700
Jensen	2000

GROUP BY More Than One Column

We can also use the GROUP BY statement on more than one column, like this:

SELECT Customer,OrderDate,SUM(OrderPrice) FROM Orders GROUP BY Customer,OrderDate