Hola martin, Intenta así:
IF @object_type = '23' AND @transaction_type in ('U','A') BEGIN IF (select count(*) from RDR1 T0 where (T0.u_campo = '' or T0.u_campo is null) and T0.DocEntry = @list_of_cols_val_tab_del)>0 begin SELECT @error= 10 SELECT @error_message = 'Tu mensaje al usuario' end end
Saludos.
Edito objtype a 23.