Chapter 11. SELECT Statement: The HAVING Clause
The purpose of the
HAVING clause of a select block is comparable to that of the
WHERE clause. The difference is that the
WHERE clause is used to select rows after the
FROM clause has been processed, whereas the
HAVING clause is used to select rows after a
GROUP BY clause has been executed. A
HAVING clause can be used without a
GROUP BY clause.
<having clause> ::= HAVING <condition>
In the previous chapter, you saw that the
GROUP BY clause groups the rows of the result from the
FROM clause. The
HAVING clause enables you to select groups (with rows) based upon their ...