SQL HAVING clause

Adding the HAVING clause to SQL is because the WHERE keyword cannot be used with the Aggregate function.

The HAVING clause has been added to SQL because the WHERE keyword cannot be used for aggregation functions.

SQL HAVING syntax 

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

Demonstrate the database

Here's a selection of "Customers" tables in the Rosevin sample database:

CustomerID CustomerName ContactName Address City PostalCode Country
1

Alfreds Futterkiste Maria Anders Obere Str. 57 Berlin 12209 Germany
2 Ana Trujillo Emparedados y helados Ana Trujillo Avda. de la Constitución 2222 México D.F. 05021 Mexico
3 Antonio Moreno Taquería Antonio Moreno Mataderos 2312 México D.F. 05023 Mexico
4

Around the Horn Thomas Hardy 120 Hanover Sq. London WA1 1DP UK
5 Berglunds snabbköp Christina Berglund Berguvsvägen 8 Luleå S-958 22 Sweden

SQL HAVING example

The following SQL statement lists the number of customers for each country. Only countries with more than 5 customers are included: 

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 from highest to below (including only countries with more than 5 customers): 

SELECT COUNT(CustomerID), Country
FROM Customers
GROUP BY Country
HAVING COUNT(CustomerID) > 5
ORDER BY COUNT(CustomerID) DESC;


Demonstrate the database

Here's an option for the Orders table in the Rosevin sample database:

OrderID CustomerID EmployeeID OrderDate ShipperID
10248 90 5 1996-07-04 3
10249 81 6 1996-07-05 1
10250 34 4 1996-07-08 2

And select from the Employees table:

EmployeeID LastName FirstName BirthDate Photo Notes
1 Davolio Nancy 1968-12-08 EmpID1.pic Education includes a BA....
2 Fuller Andrew 1952-02-19 EmpID2.pic Andrew received his BTS....
3 Leverling Janet 1963-08-30 EmpID3.pic Janet has a BS degree....

More HASING examples

The following SQL statement lists employees who 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 whether an employee "Davolio" or "Fuller" has 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;