How can I check whether a number is contained in comma separated list stored in a varchar column?

Question

I have a table with a varchar column categoryIds. It contains some IDs separated by commas, for example:

id       categoryIds
-----         


        

Answer 1

You should really redesign this table to split out those values from being comma separated to being in individual rows. However, if this is not possible, you are stuck with doing string comparison instead:

DECLARE @id INT = 3
DECLARE @stringId VARCHAR(50) = CAST(@id AS VARCHAR(50))

SELECT * 
FROM MyTable 
WHERE categoryIds = @stringId -- When there is only 1 id in the table
OR categoryIds LIKE @stringId + ',%' -- When the id is the first one
OR categoryIds LIKE '%,' + @stringId + ',%' -- When the id is in the middle
OR categoryIds LIKE '%,' + @stringId -- When the id is at the end