Ora-01744 error inapproriate into

Question

create or replace FUNCTION BILLING_AMOUNT (p_bill_key IN varchar2) RETURN NUMBER AS
   l_total    NUMBER;
   l_dum_bill NUMBER;
   p_count NUMBER:=0;
BEGIN
   BEGIN
      SELECT count(*) into p_count
      FROM billing_adjust b    where    b.billing_key = p_bill_key and approval_flag='A';
if p_count < 1 then
         SELECT BILLING_AMOUNT
         into l_total FROM mv_billing a
      WHERE  a.billing_key = p_bill_key
      UNION
      SELECT BILLING_AMOUNT
         into l_total     FROM billing a
      WHERE  a.billing_key = p_bill_key;
return  l_total  ;
end if;
   SELECT CORRECT_AMOUNT
     into l_total      FROM mv_billing_adjust b
      WHERE b.billing_key = p_bill_key
      union
      SELECT CORRECT_AMOUNT
       into l_total       FROM billing_adjust b
      WHERE b.billing_key = p_bill_key ;
return l_total;
EXCEPTION  
    WHEN NO_DATA_FOUND THEN
    null; 
End;
   RETURN 0;
END BILLING_AMOUNT;since i am getting error from above so i changed it to the following. can i change the above code to below.
create or replace FUNCTION BILLING_AMOUNT1 (p_bill_key IN varchar2) RETURN NUMBER AS
   l_total    NUMBER;
   l_dum_bill NUMBER;
   p_count NUMBER:=0;
cursor c1 is
SELECT count(*) v_count
      FROM billing_adjust b    where    b.billing_key = p_bill_key and approval_flag='A'
union
SELECT count(*) v_count
      FROM billing_adjust b    where    b.billing_key = p_bill_key and approval_flag='A';
cursor c2 is
SELECT BILLING_AMOUNT
               FROM mv_billing a
      WHERE  a.billing_key = p_bill_key
union
SELECT BILLING_AMOUNT
             FROM billing a
      WHERE  a.billing_key = p_bill_key ;
cursor c3 is
SELECT CORRECT_AMOUNT
         FROM mv_billing_adjust b
      WHERE b.billing_key = p_bill_key
union
SELECT CORRECT_AMOUNT
             FROM billing_adjust b
      WHERE b.billing_key = p_bill_key ;
BEGIN
   BEGIN
      For v1 in c1 loop
         p_count:=v1.v_count;
      End loop;
if p_count < 1 then
         for v2 in c2 loop
         l_total:=v2.BILLING_AMOUNT;     
return  l_total  ;
end loop;
end if;
   for v3 in c3 loop
     l_total:=v3.correct_AMOUNT;  
return l_total;
end loop;
EXCEPTION  
    WHEN NO_DATA_FOUND THEN
    null; 
End;
   RETURN 0;
END BILLING_AMOUNT1;i am not getting any error with this code.

Answer 1

Error in First piece of code -
You cannot store 2 values in the same variable in the same query with the help of a union.
If you are trying to add the amounts , use something like -
SELECT SUM (billing_amount)
  INTO l_total
  FROM (SELECT billing_amount
          FROM mv_billing a
         WHERE a.billing_key = p_bill_key
        UNION
        SELECT billing_amount
          FROM billing a
         WHERE a.billing_key = p_bill_key);Second piece of code really has some issues reg the logic - [not very clear what u trying to achieve]
CREATE OR REPLACE FUNCTION billing_amount1 (p_bill_key IN VARCHAR2)
   RETURN NUMBER
AS
   l_total      NUMBER;
   l_dum_bill   NUMBER;
   p_count      NUMBER := 0;
   CURSOR c1
   IS
      SELECT COUNT (*) v_count
        FROM billing_adjust b  -- what are you trying to do here ???   using same query twice n UNION
       WHERE b.billing_key = p_bill_key AND approval_flag = 'A'
      UNION
      SELECT COUNT (*) v_count
        FROM billing_adjust b
       WHERE b.billing_key = p_bill_key AND approval_flag = 'A';
   CURSOR c2
   IS
      SELECT billing_amount
        FROM mv_billing a
       WHERE a.billing_key = p_bill_key
      UNION
      SELECT billing_amount
        FROM billing a
       WHERE a.billing_key = p_bill_key;
   CURSOR c3
   IS
      SELECT correct_amount
        FROM mv_billing_adjust b
       WHERE b.billing_key = p_bill_key
      UNION
      SELECT correct_amount
        FROM billing_adjust b
       WHERE b.billing_key = p_bill_key;
BEGIN
   BEGIN
      FOR v1 IN c1
      LOOP
         p_count := v1.v_count;  -- you will get same count 2 times as 2 records  ....
      END LOOP;
      IF p_count < 1
      THEN
         FOR v2 IN c2
         LOOP
            l_total := v2.billing_amount;
            RETURN l_total;
         END LOOP;
      END IF;
      FOR v3 IN c3
      LOOP
         l_total := v3.correct_amount;
         RETURN l_total;
      END LOOP;
   EXCEPTION
      WHEN NO_DATA_FOUND
      THEN
         NULL;
   END;
   RETURN 0;
END billing_amount1;If you have any requirement, post table DDL scripts, sample INSERT Statements, expected output, then only many ppl here can help in a better way.