ORA-00979

Error: ORA-00979: not a GROUP BY expression

Causa: The GROUP BY clause does not contain all the expressions in the SELECT clause. SELECT expressions that are not included in a group function, such as AVG, COUNT, MAX, MIN, SUM, STDDEV, or VARIANCE, must be listed in the GROUP BY clause.

Acción: Include in the GROUP BY clause all SELECT expressions that are not group function arguments.