The GROUP BY clause must contain every column in the SELECT clause,as well as every aggregate expression in the SELECT clause,or the query will not be valid.

Question

Quizplus · Accepted Answer

The GROUP BY clause does not need to contain every column in the SELECT clause, only those columns that are not part of an aggregate function. Aggregate functions can be included in the SELECT clause without being in the GROUP BY clause.

The GROUP BY Clause Must Contain Every Column in the SELECT