SQL problem - joins plus sub query (Paradox7)

D2.0, C/S, W95
Is there a problem or an SQL limitation when trying to select from two
tables with a join, and also use a subquery?
For example, I'm using 3 tables: Company,  Contacts and internal contacts
(both the two contacts tables relate to the company table).


CXCoFK          (foreign key to company table)

ICCoFK          (foreign key to company table)
ICStaff         (Staff Number)

The query I want is all companies who have a contact called Joe AND whose
internal contact (eg account manager) is Fred (who is person 2 in a staff
This gives a query such as:
select CompanyID, CompanyName, ContactName from Company, Contacts
where CXCoFK=CoID and CXName='Joe'
and CoID in (select ICCoFK from IntCont where ICStaff=2)

This doesn't give an error but ingores the subquery, even if I change the
last line to
and CoID in (12)
(which should return a maximum of one row, but it shows all the Joes).

BTW, if I use the same subquery against a single table (no join) then it
works fine, eg
Select CoName from Company where CoID in (select ICCoFK from IntCont
where ICStaff=2)

Any idea why this happens, or can you suggest a workaround?

Please could you email a reply as well, as I don't always have access to
the newsgroup.
Thanks, David Carle