A HAVING
clause in SQL specifies that an SQL SELECT
statement should only return rows where aggregate values meet the specified conditions. It was added to the SQL language because the WHERE
keyword could not be used with aggregate functions.[1]
To return a list of department IDs whose total sales exceeded $1000 on the date of January 1, 2000, along with the sum of their sales on that date:
SELECT DeptID, SUM(SaleAmount) FROM Sales WHERE SaleDate = '01-Jan-2000' GROUP BY DeptID HAVING SUM(SaleAmount) > 1000
Referring to the sample tables in the Join (SQL) example, the following query will return the list of departments who have more than 1 employee:
SELECT DepartmentName, COUNT(*) FROM employee,department WHERE employee.DepartmentID = department.DepartmentID GROUP BY DepartmentName HAVING COUNT(*)>1;
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