| ERROR | Duplicate group-by clause in table expression |
| CAUSE | Two or more GROUP BY clauses were found in a SELECT statement. The GROUP BY clause lists column expressions used to form a summary row for each group of selected rows. The list can contain several column expressions separated by commas, but a statement can contain only one GROUP BY clause. |
| ACTION | Remove one of the GROUP BY clauses and, if necessary, separate column expressions by commas. |