SQL GROUP BY

SQL GROUP BY Description

The GROUP BY statement groups rows with the same values ​​into summary rows, such as "find the number of customers in each country".

The GROUP BY statement is often used with aggregate functions (COUNT(), MAX(), MIN(), SUM(), AVG()) to group a result set by one or more columns.

GROUP BY Syntax

SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
ORDER BY column_name(s)

Demonstration database

The following is a sample from the "Customers" ("Customers") table of the "Northwind" database:

SQL GROUP BY Examples

The following SQL statement lists the number of customers in each country:

Run SQLSELECT COUNT(CustomerID), Country 
FROM Customers 
GROUP BY Country

The following SQL statement lists the customers in each country, sorted from highest to lowest:

Run SQLSELECT COUNT(CustomerID), Country 
FROM Customers 
GROUP BY Country 
ORDER BY COUNT(CustomerID) DESC

Demonstration database

The following is a sample from the "Orders" ("Orders") table of the "Northwind" database:

And the sample from the table "Shippers" ("Senders"):

GROUP BY together with JOIN Example

The following SQL statement lists the number of orders sent by each sender:

Run SQLSELECT Shippers.ShipperName, COUNT(Orders.OrderID) AS NumberOfOrders 
FROM Orders 
LEFT JOIN Shippers 
ON Orders.ShipperID = Shippers.ShipperID 
GROUP BY ShipperName