Thanks,
________________________________________
From: firebird-support@yahoogroups.com [mailto:firebird-support@yahoogroups.com] On Behalf Of fabiano_bonin
Sent: Tuesday, July 26, 2005 2:47 PM
To: firebird-support@yahoogroups.com
Subject: [firebird-support] Re: problem with multicolumn subselect

--- In firebird-support@yahoogroups.com, Pavel Menshchikov
<mpn2001@y...> wrote:

> Hello Jeremy,
>
> WJ> Select min (col1)
> WJ> From table1
> WJ> Where (col2, col3) in
> WJ>  (select col4, col5 from table2 where col6 = variable);
>
> I guess in FB it should be
>
> Select min (col1)
> From table1
> Where col2 in
>  (select col4 from table2 where col6 = variable) and
>  col3 in
>  (select col5 from table2 where col6 = variable);
>

Or, preferably:

select
  min(col1)
from
  table1
where
  exists ( select * from table2 where col4 = table1.col2 and col5 =
table1.col3 and col6 = variable )

This way FB will make use of indices if available, and your query will
be much faster.

Regards,

Fabiano.





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