Removing duplicate concatenated values in a sql column - sql

Question

I am updating a product bin location in our database using the reference text from a stock count we recently did. Some of the products have multiple bin locations, so I am using this SQL to pull all the bin locations into a table:
SELECT
SCT.ProductID,
STUFF ((SELECT ',' + ReferenceText
FROM StockCounttickets SCT2
WHERE SCT2.ProductId = SCT.ProductID
AND SCT2.StockCountID = '10873'
ORDER BY ProductID
FOR XML PATH(''), TYPE).value('.', 'varchar(max)'), 1, 1, '') AS Products
FROM
StockCountTickets SCT
WHERE
SCT.StockCountID = '10873'
GROUP BY
ProductID ;
I am getting the result I want, except for some of the products were counted twice in the same place, so some of the results have the same value twice
Is there any way to get rid of the duplicates?

Answer 1

Presumably, you mean the duplicates in the concatenated list.
Well, you can just remove the duplicates using select distinct or group by:
SELECT SCT.ProductID,
STUFF( (SELECT DISTINCT ',' + SCT2.ReferenceText
FROM StockCounttickets SCT2
WHERE SCT2.ProductId = SCT.ProductID AND
SCT2.StockCountID = 10873
ORDER BY SCT2.ProductID
FOR XML PATH(''), TYPE).value('.', 'varchar(max)'
), 1, 1, '') AS Products
FROM (SELECT DISTINCT SCT.ProductId
FROM StockCountTickets SCT
WHERE SCT.StockCountID = 10873
) SCT;
Notes:
In a correlated subquery, you should qualify all column references, always, to avoid errors.
Assuming StockCountID is a number, don't use quotes for the comparison.
I prefer to generate the distinct rows in the subquery. I believe this is a performance gain.