Microsoft KB Archive/63868

INF: GROUP BY Function Only Returns Rows ID Number: Q63868

1.10 1.11 4.20 OS/2

Summary:

The following is an explanation of why the GROUP BY function only returns rows.

The GROUP BY function requires that all items in the select list either be aggregates or have the same value for all members of the group. This is because the GROUP BY function returns a single row for the entire group and there is no way to display different values for individual members of the group.

If the select list includes items that cannot be summarized into a single line for the entire group, SQL Server returns a row for each individual member of the group. If a HAVING clause is present, it is ignored because it is applicable only when the GROUP BY function is used.

Additional reference words: 1.10 1.11 4.20 Transact-SQL