>Hi,
>
>In order to make sure that my SQL Select will work (different from the one I use here as an example) I need to understand how sub-queries work.
>
>Here is a sample SQL Select:
>

>select fk_fld, flda, fldb from Table1 where fk_fld IN (select pk_fld from Table2 where <somecondition> 
>   group by pk_fld)
>

>
>My question is, does VFP (or SQL server) when executing the above SQL Select executes the sub-query first (one time) and then executes main query checking every record of Table1 to see if value FK_FLD is in sub-query?
>
>TIA.

Yes, this is how it's executed. I prefer using EXISTS subquery, though, instead of IN/NOT IN. It may perform faster than IN subquery.