DB2 - Ways to get multiple positions for character in a string - sql

Question

So I am having the pleasure of working with a very old database that apparently was setup before the invention of normalization. I have been asked to see if I can come up with a way to make it work right.
The first table actually has something like a real primary key.
example:
ID, Reason
--- ----------
1, Write off
2, Overage
3, OLH
The problem is the other table...
CustomerNum, JobNum, Reasons
------------ ------- ---------------------
42351, 46, X
32313, 456, X
85472, 13, X X
How are these tables joined in their system? Yup, the position of the X's in the line. So if the X is in the first position, it's the reason 1, second position, reason 2, and so on. It's essentially a flat array. And that wouldn't be to bad actually, if they limited it to 1 X per line... (LOCATE('X', REASONS) as XINDEX) but that's not the case. In theory there are 21 possible X's that could be checked on each line.
So I have to give them a recommendation on how to make it work.
One of my first recommendations will be to create a separate table and normalize the tables, however I don't know how well that will go over, or if they would be willing to change their system.
So, I would also like to suggest something like a stored procedure that would be able to go through each line and return the indexes as if they were in a separate table.
I don't know if this is possible, but I'm hopeful.
EDIT
So yeah, I'm really going to push the linking table.
here's the alternative that I've got working from the suggestions:
Select tblCustomers.*,
CASE WHEN SUBSTRING(Reasons,1,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 1)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,2,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 2)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,3,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 3)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,4,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 4)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,5,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 5)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,6,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 6)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,7,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 7)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,8,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 8)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,9,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 9)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,10,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 10)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,11,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 11)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,12,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 12)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,13,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 13)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,14,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 14)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,15,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 15)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,16,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 16)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,17,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 17)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,18,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 18)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,19,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 19)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,20,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 20)) || ', ' ELSE '' END
|| CASE WHEN SUBSTRING(Reasons,21,1) = 'X' THEN RTRIM((SELECT Reason FROM tblReasons WHERE ID = 21)) || ', ' ELSE '' END AS XPOS
From tblCustomers
I'm going to have to play with Marlin's suggestion a bit to see how much it streamlines it, but one thing I do like about this query is that it shows how ridiculous their current layout is, and why they should change it.

Answer 1

I'd really pitch the new linking table, but here is either the meat of the stored procedure, or the way to populate the linking table:
SELECT Customers.CustomerNum, Reasons.ID
FROM Customers, Reasons
WHERE SUBSTR(Customers.Reasons, Reasons.ID, 1) = 'X'

Answer 2

first thing I would do is to create a new column for each possible position of the X (so if there are 10 positions -> 10 new cols) and give those columns meaningful names. then you can write queries easier...