The HAVING clause sets conditions on the GROUP BY clause similar to the way that WHERE interacts with SELECT. The HAVING clause’s important characteristics are:
The HAVING clause comes after the GROUP BY clause and before the ORDER BY clause.
Just as WHERE limits the number of rows displayed by SELECT, HAVING limits the number of groups displayed by GROUP BY.
The WHERE search condition is applied before grouping occurs, and the HAVING search condition is applied after.
HAVING syntax is similar to the WHERE syntax, except that HAVING can contain aggregate functions.
A HAVING clause can reference any of the items that appear in the SELECT list.
The sequence in which the WHERE, GROUP BY, and HAVING clauses are applied is: ...