Having Statement

When you are doing a summary query, you can also specify a Having Statement. This is like a Where statement, except that it involves a summary value, rather than a column value.

In the example of customer revenue, the following query shows you customer revenue when it is more than $1000:

SELECT customer_code, month, sum(revenue)

FROM Orders GROUP BY customer_code, month

HAVING sum(revenue) > 1000

Here the HAVING clause has sum(revenue), which can only be determined after the table has been summarized.

Having versus Where

The easiest way to understand the difference between a Where clause and a Having clause is as follows.

A Where clause specifies the rows in your table to be included in the summarization calculation
The Having clause operates after the summary calculation has been done. It specifies which of the summarized rows are returned by the query.

Advanced Query Tool

https://www.querytool.com