Suggestion follows:

*!* Your original SQL
select G.cStyle, G.kGarment, G.cDescrip, G.nDefPrice ;
  from Garments G ;
 where lkLoc in (select LG.kLoc from LocGarment LG ;
                  where LG.kGarment = G.kGarment   )

*!* Proposed Solution
SELECT G.cStyle, G.kGarment, G.cDescrip, G.nDefPrice ;
FROM Garments G ;
     JOIN LocGarment LG ON ;
          LocGarment.kLoc = Garments.lkLoc ;

What you're really doing is limiting Garments by a PK/FK 1:M relation in LocGarment. A simple INNER JOIN between the two will limit Garments to what is also in LocGarment. Am I seeing the problem-solution pair correctly here?