JOIN to change string in column cells - sql

Question

I am working on a query that gets 2 columns from different tables based on JOIN associations:
SELECT DISTINCT co.item_name
,SUBSTRING((
SELECT ',' + ca.attr_val AS [text()]
FROM [CONTRACT_ATTR] CA
WHERE CA.Item_Id = CO.Item_Id
AND ca.field_id = 239
ORDER BY co.item_name
FOR XML PATH('')
), 2, 1000) GM_PROG
FROM [dbo].[CONTRACT] CO;
The 2nd column has numbers and those numbers are keys on a lookup table.
I am trying to figure out how to change the numbers into the correct item_name.
I believe it has to do with the query inside the substring:
SELECT ','+ca.attr_val AS [text()]
FROM [CONTRACT_ATTR] ca
JOIN GM_PROGRAM gm
ON ta.GM_PROG = gm.item_id
WHERE CA.Item_Id = CO.Item_Id
AND ca.field_id = 239
ORDER BY co.item_name
FOR XML PATH ('') ta
), 2, 1000) GM_PROG
This is where I'm at. I doesn't run and I think this is because its trying to reference.
What am I doing wrong and how do I fix it?

Answer 1

You are close, you just need to change ca.attr_val to gm.item_name, your join referenced ta instead of ca (typo I would guess), and probably sort on gm.item_name instead of co.item_name in the subquery:
SELECT DISTINCT co.item_name
,SUBSTRING((
SELECT ',' + gm.item_name AS [text()]
FROM [CONTRACT_ATTR] CA
inner join GM_PROGRAM gm
ON ca.attr_val = gm.item_id
WHERE CA.Item_Id = CO.Item_Id
AND ca.field_id = 239
ORDER BY gm.item_name
FOR XML PATH('')
), 2, 1000) GM_PROG
FROM [dbo].[CONTRACT] CO;