If both nonaggregated and aggregated columns are used in the SELECT clause,the GROUP BY clause must contain the nonaggregated columns.

Question

​If both nonaggregated and aggregated columns are used in the SELECT clause,the GROUP BY clause must contain the nonaggregated columns.

Quizplus · Accepted Answer

This is because the nonaggregated columns determine how the data is grouped, while the aggregated columns perform calculations on the grouped data. If nonaggregated columns are not included in the GROUP BY clause, the database may not know how to group the data correctly.

​If Both Nonaggregated and Aggregated Columns Are Used in the SELECT

If Both Nonaggregated and Aggregated Columns Are Used in the SELECT