ORA-01422,,, Very Strange Error in my code!!!

Question

Dear,
I need your help please,,,
I have the below code in a database package which always throws (ORA-01422)
SELECT (NVL(amount,0) - NVL(cash_disc,0)) INTO v_bill_amount
FROM pac_bills
WHERE pac_bills.bill_no = v_bill_no AND pac_bills.bill_type = 3;
Now when I execute this code I get (ORA-01422) for v_bill_no = 207000003. when I execute same statement from TOAD or SqlPlus IT RETURN ONE ROW ONLY!!! for same bill_no
This error make me mad and I need any help

Answer 1

I would try to see what extra rows are selected in the pacakage. If it's a database package then it could be something like this:
/* Temp table to register selected rows */
CREATE TABLE Tmp_Debug(
  TS TIMESTAMP, /* to identify different statement executions */
  bill_no INTEGER,
  r ROWID
/* DEBUG fragment to be inserted into the package */
DECLARE
  PROCEDURE Trace(
    p_bill_no INTEGER
  ) IS
    PRAGMA AUTONOMOUS_TRANSACTION;
  BEGIN
    INSERT INTO Tmp_Debug(ts, bill_no, r)
      SELECT systimestamp, p_bill_no, (NVL(amount,0) - NVL(cash_disc,0))
      FROM pac_bills
      WHERE pac_bills.bill_no = p_bill_no AND pac_bills.bill_type = 3;
    COMMIT;
  END;
BEGIN
  /* Original select */
  SELECT (NVL(amount,0) - NVL(cash_disc,0)) INTO v_bill_amount
  FROM pac_bills
  WHERE pac_bills.bill_no = v_bill_no AND pac_bills.bill_type = 3;
EXCEPTION
  WHEN TOO_MANY_ROWS THEN
    Trace(v_bill_no);
END;
/* End of DEBUG fragment */Reproduce the error and see in Tmp_Debug, what rows are actually selected. Sure I didn't test it.
If it's a forms package then you may implement some debug form or something else to see the actually selected rows.
One more thought: is it possible that app logic produces extra rows? They are not commited and rolled back after the error, this is why you can't see them in TOAD/Sql*Plus.
Regards,
Dima.