Try this SP.
IF (@object_type='17' and ( @transaction_type='A' OR @transaction_type='U'))
Begin
if exists
(SELECT T0.docentry, t1.itemcode FROM ORDR T0 INNER JOIN RDR1 T1 ON T0.[DocEntry] = T1.[DocEntry] INNER JOIN OITM T2 ON T1.[ItemCode] = T2.[ItemCode] WHERE T2.[U_custname] = T0.[CardCode] and T0.[Docentry] =@list_of_cols_val_tab_del )
begin
set @error='1001'
SET @error_message='Invalid item no '
end
End
Thanks