HAVING
The HAVING clause was added to SQL because the WHERE clause cannot be used with aggregate functions.
Aggregate functions are often used with GROUP BY clauses, and by adding HAVING we can write condition like we do with WHERE clauses.
Example
SELECT COUNT(customer_id), country
FROM customers
GROUP BY country
HAVING COUNT(customer_id) > 5;
More HAVING Examples
The following SQL statement lists only orders with a total price of 400$ or more:
Example
SELECT order_id, SUM(order_details.quantity * products.price)
FROM order_details
LEFT JOIN products on products.product_id = order_details.product_id
GROUP BY order_id
HAVING SUM(order_details.quantity * products.price) > 400.00;
Lists customers that have ordered for 1000$ or more:
Example
SELECT customers.customer_name,
SUM(order_details.quantity * products.price)
FROM order_details
INNER JOIN products ON order_details.product_id = products.product_id
INNER JOIN orders ON order_details.order_id = orders.order_id
INNER JOIN customers ON orders.customer_id = customers.customer_id
GROUP BY customers.customer_id, customers.customer_name
HAVING SUM(order_details.quantity * products.price) >= 1000;
