Thanks.

I am assuming that EXISTS will do a separate lookup for each record, and will therefore be slow with large tables. Any comments about this assumption?

>You can use EXISTS query or concatenate fields

>... where EXISTS (select * from Table2 WHERE KeyField = Table1.KeyField AND KeyField2 = Table1.KeyField2 )
>
>... where KeyField1 + KeyField2 in (select KeyField + KeyField2 from Table2)
>
>

>
>>Is it possible to do I do a subquery with two key fields (or join fields)?
>>
>>For example, with a single keyfield, I would write:
>>
>>

>>select * from Table1;
>>  where KeyField in (select KeyField from Table2)
>>

>>
>>With two fields, I would need something like the following:
>>
>>

>>... where KeyField1, KeyField2 in (select KeyField, KeyField2 from Table2)
>>

>>
>>But I am not sure whether this is possible at all, and if it is, what the syntax would be.
>>
>>In the meantime, I am using JOIN syntax, which works OK... but I am still curious if the subquery with two join fields is possible.