The HAVING
clause was added to SQL because the
WHERE
keyword cannot be
used with aggregate functions.
SELECT column_name(s)
FROM table_name
WHERE condition
GROUP BY column_name(s)
HAVING condition
ORDER BY
column_name(s);
The following SQL statement lists the number of customers in each country. Only include countries with more than 5 customers:
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5;
The following SQL statement lists the number of customers in each country, sorted high to low (Only include countries with more than 5 customers):
SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID)
> 5
ORDER BY COUNT(CustomerID) DESC;
The following SQL statement lists the employees that have registered more than 10 orders:
SELECT Employees.LastName, COUNT(Orders.OrderID) AS NumberOfOrders
FROM
(Orders
INNER JOIN Employees ON Orders.EmployeeID = Employees.EmployeeID)
GROUP BY LastName
HAVING COUNT(Orders.OrderID) > 10;
The following SQL statement lists if the employees "Davolio" or "Fuller" have registered more than 25 orders:
SELECT Employees.LastName, COUNT(Orders.OrderID) AS NumberOfOrders
FROM Orders
INNER JOIN Employees ON Orders.EmployeeID = Employees.EmployeeID
WHERE LastName = 'Davolio' OR LastName = 'Fuller'
GROUP BY LastName
HAVING
COUNT(Orders.OrderID) > 25;