Re: SQL question: GROUP BY and MAX

In article <9eg8q3$np8$1_at_news.tue.nl>, hidders_at_REMOVE.THIS.win.tue.nl says...
> SELECT a
> FROM tabA
> GROUP BY a
> HAVING COUNT(*) = 5;
>
> This is equal to:
>
> SELECT DISTINCT a
> FROM tabA r1
> WHERE ( SELECT COUNT(*)
> FROM tabA r2
> WHERE r1.a = r2.a ) = 5;

        Would there/should there be performance differences, geenrally speaking? or, would most advanced db's SQL optimizers reduce it to the same operations? Thanks.

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Paul Tiseo, Intermediate Systems Programmer
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