HAVING Clause
Allows filtering the aggregation results produced by GROUP BY. It is similar to the WHERE clause, but the difference is that WHERE is performed before aggregation, while HAVING is performed after it.
It is possible to reference aggregation results from SELECT clause in HAVING clause by their alias. Alternatively, HAVING clause can filter on results of additional aggregates that are not returned in query results.
Example
If you have a sales table as follows:
You can query it like so:
This will list sales people with greater than 10,000 in total sales in their region.
Limitations
HAVING can't be used if aggregation is not performed. Use WHERE instead.