SubQueries Not Allowed

Question

Hello,
I am trying to run the below querry in my proc but get an error that "Subqueries currently (8.1.7) not allowed outside SQL" Below is the querry.
     IF v_TransCode = 'A'
          AND v_DocNum In(Select Document_Number from T_PIOS_MASTER where T_PIOS_MASTER.Document_number = v_DocNum) THEN
               RAISE_APPLICATION_ERROR(-20100,'Error Add PIOS Master Already Exist');
     END IF;

Answer 1

You cannot specify SELECT ..... as a condition for IF statement. Try something like:
IF v_TransCode = 'A' THEN
   SELECT count(*)
     INTO n
     FROM T_PIOS_MASTER
    WHERE T_PIOS_MASTER.Document_number = v_DocNum;
   IF n > 0 THEN
      RAISE_APPLICATION_ERROR(-20100,'Error Add PIOS Master Already Exist');
   END IF;  
END IF;