To filter the result returned from the
GROUP BY clause, we use
HAVING clause. Remember that we can’t use WHERE clause to filter records with the GROUP BY clause.
SELECT LastName, SUM(NetSalary) AS NetSalary, SUM(PPFDeduction) AS PPFDeduction FROM viewPersonalAccounts GROUP BY LastName HAVING LastName = 'Narayan'
In the above statement, we have filtered the result of GROUP BY having LastName = ‘Narayan’.
Similarly, we can also filter by the SUM of either NetSalary or PPFDeduction.
Only those fields are allowed in the HAVING clause that is the part of SELECT statement. If SELECT statement has Aggregate function with column names, HAVING clause must have that Aggregate functions with the column name.
Like, below statement will not work
SELECT LastName, SUM(NetSalary) AS NetSalary, SUM(PPFDeduction) AS PPFDeduction FROM viewPersonalAccounts GROUP BY LastName HAVING PPFDeduction > 10000
As the SELECT statement has SUM aggregate functions with the PPFDeduction but HAVING is directly trying to compare the value of PPFDeduction column. To solve this problem, we can have SUM function in the PPFDeduction column as well after HAVING clause.Views: 1419 | Post Order: 52