Hi, BLTGSI hope it is a field.... So if none maps in your situations then it goes to this expression, " 'AT' & 'DEAT' & BLTGS1 ". But here if you look at it, it doesn't know internally which value of it to concatenate. For example , BLTGS1 contains A1,B2,B4,Y6 then from your expression point of view, ATDEAT___ which value should be replaced. So try giving any other alternative.