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Yes does affect the outcome if B and C and D is NOT a primary or unique key
Jimmy heeft geschreven in bericht <37F5DB19.5363BFB9_at_comp.polyu.edu.hk>...
>Hello all,
>
> Assume I have a table with column A, B, C and D.
>
> I wonder the following SQL statements will produce the same results:
>
> i) select B, C, D, avg(A) from AAA group by B, C, D;
> ii) select B, C, D, avg(A) from AAA group by B, D, C;
> iii) select B, C, D, avg(A) from AAA group by C, B, D;
> ....
>
> i.e. does the order of group by clause affect the final result (or
>performance, if any) of the SQL statement? Anyone knows white papers or
>documents discussing this issue?
>
>Thanks,
>Jimmy
>
>
>
>
Received on Fri Oct 01 1999 - 15:06:41 CDT