Trouble with OR in where clause

Question

Hello,
I'm having trouble with execution speed. The problem seems to be with using OR in my where clause.
Here's the meat of the function where i_pledge_number is an input parm:
BEGIN
SELECT /*+ INDEX (pp) */ SUM(pp.prim_pledge_amount)
INTO return_amount
FROM
primary_pledge pp
WHERE
-- Get total if multiple allocations
pp.prim_pledge_number IN
(SELECT pc.pledge_number
FROM pledge_codes pc
WHERE pc.pledge_code_type = 'M'
AND pc.pledge_code = 'AC'
AND lpad(pc.pledge_comment,10,'0') = i_pledge_number)
-- Get total if single allocation
OR pp.prim_pledge_number = i_pledge_number;
RETURN return_amount;
END;
If I comment out either half of the OR statement (either the subquery or the pp.prim_pledge_number = i_pledge_number half) the function returns a value in .02 seconds. If I leave the OR in, it takes 2.764 seconds to execute?? Can someone please show me a better way (faster) to do this? I tried using nvl() around the subquery but couldn't get it to compile.
Thanks

Answer 1

These things are difficult to diagnose remotely, but here is something you can try....
SELECT */ SUM(pp.prim_pledge_amount)
INTO return_amount
FROM   primary_pledge pp
WHERE  pp.prim_pledge_number IN (SELECT pc.pledge_number
                                 FROM pledge_codes pc
                                 WHERE pc.pledge_code_type = 'M'
                                 AND pc.pledge_code = 'AC'
                                 AND lpad(pc.pledge_comment,10,'0') = i_pledge_number
UNION ALL
SELECT i_pledge_number FROM dual)
   RETURN return_amount;
END;If that doesn't do anything (and it might well not) there are a large number of different ways we can recast this query. To save us further guessing please give us more details: execution plans, database version number, volumetrics.
Cheers, APC