How do I use a comma separated list of values as a filter in T-SQL?

Question

I have a basic SQL query, starting with:

SELECT top 20 application_id, [name], location_id FROM apps

Now, I would like to finish it so that it

Answer 1

See this entry in my blog:

• IN with a comma separated list: SQL Server

If your @lid is a comma-delimited list of integers, use this:

WITH    cd AS
        (
        SELECT  1 AS first, CHARINDEX(',', @lid, 1) AS next
        UNION ALL
        SELECT  next + 1, CHARINDEX(',', @lid, next + 1)
        FROM    cd
        WHERE   next > 0
        ),
        lid AS
        (
        SELECT  CAST(SUBSTRING(@lid, first, CASE next WHEN 0 THEN LEN(@lid) + 1 ELSE next END - first)AS INT) AS id
        FROM    cd
        )
SELECT  d.*
FROM    (
        SELECT  DISTINCT id
        FROM    lid
        ) l
JOIN    apps a
ON      a.location_id = l.id
        AND @lid <> '0'
UNION ALL
SELECT  *
FROM    apps a
WHERE   @lid = '0'

This is much more efficient than using OR constructs.