Sams Teach Yourself SQL in 24 Hours, Second Edition

The HAVING Clause

The HAVING clause, when used in conjunction with the GROUP BY in a SELECT statement, tells GROUP BY which groups to include in the output. HAVING is to GROUP BY as WHERE is to SELECT. In other words, the WHERE clause places conditions on the selected columns, whereas the HAVING clause places conditions on groups created by the GROUP BY clause.

The following is the position of the HAVING clause in a query:

SELECT
FROM
WHERE
GROUP BY
HAVING
ORDER BY

The HAVING clause must follow the GROUP BY clause in a query and must also precede the ORDER BY clause if used.

The following is the syntax of the SELECT statement, including the HAVING clause:

 SELECT COLUMN1, COLUMN2 FROM TABLE1, TABLE2 WHERE CONDITIONS GROUP BY COLUMN1, COLUMN2 ...