[SQL] trying to do an update a bit confused.

[Joel Fradkin]

update tblcase  set merchandisetotal = ( COALESCE(( SELECT sum(m.quantity::numeric * m.amount) AS merchandiseamount            FROM tblmerchandise m           WHERE m.caseid = tblcase.caseid AND m.clientnum::text = tblcase.clientnum::text), 0.0) )   I tried running the above and it wants to do a sum on all the records in tblcase instead of just the one being updated, what am I doing wrong?   Joel Fradkin