On 24 Feb 2005 at 9:11, Alberto Pesce wrote:

>why this union don't work:
>
>SELECT SUM(A), B, C, D
>FROM X,T,Z
>WHERE set_condition_1
>GROUP BY B, C, D, A
>ORDER BY B

Because grouping and ordering in parts of union is impossible. Only
whole result set can be grouped and sorted.
--
SY, Dimitry Sibiryakov.