SQL HAVING Clause

What does the HAVING clause do in a query?

• HAVING is like WHERE but operates on grouped records returned by a GROUP BY.
• HAVING applies to summarized group records, whereas WHERE applies to individual records.
• Only the groups that meet the HAVING criteria will be returned.
• HAVING requires that a GROUP BY clause is present.
• WHERE and HAVING can be used in the same query.

The SQL HAVING syntax

The general syntax is

SELECT column-names
  FROM table-name
 WHERE condition
 GROUP BY column-names
HAVING condition

SELECT column-names
  FROM table-name
 WHERE condition
 GROUP BY column-names
HAVING condition
 ORDER BY column-names

SQL GROUP BY Examples

SELECT COUNT(Id), Country 
  FROM Customer
 GROUP BY Country
HAVING COUNT(Id) > 10

SELECT COUNT(Id), Country 
  FROM Customer
 WHERE Country <> 'USA'
 GROUP BY Country
HAVING COUNT(Id) >= 9
 ORDER BY COUNT(Id) DESC

SELECT AVG(TotalAmount), FirstName, LastName
  FROM [Order] O JOIN Customer C ON O.CustomerId = C.Id
 GROUP BY FirstName, LastName
HAVING AVG(TotalAmount) BETWEEN 1000 AND 1200