Oracle Error PLS-00604: aggregate function is not allowed here

Oracle Error Message

PLS-00604: aggregate function is not allowed here

Reason for the Error

One of the functions, such as AVG, COUNT, MAX, MIN, SUM, STDDEV or VARIANCE, was used in a WHERE or GROUP BY clause

Solution

Remove the group function from the WHERE or GROUP BY clause. The desired result may be achieved by including the function in a subquery or HAVING clause.