Select rows from comma collected ids in a column

Question

My db is:

# item_rel
id | item_ids
--------------------------
1  | 1,2,4,6,8,10
2  | 3,5,7
3  | 9,11,12
.. | ............

# items
id | name
--------------------------
1  | Lorem
2  | Ipsum
3  | Sed
4  | Amed
.. | ............

The problem is select items with one query. I have tried many way but no luck. Only this one approachs the expected result:

SELECT
    items.*
FROM
    items
WHERE
    items.id IN (
        SELECT
            items_rel.ids
        FROM
            items_rel
        WHERE
            items_rel.ids LIKE "1" OR
            items_rel.ids LIKE "1,%" OR
            items_rel.ids LIKE "%,1" OR
            items_rel.ids LIKE "%,1,%"
    )

This query returns only one item.. How to get every item with one query?

Answer 1

This was a bit tricky, but was so not imposible, nor a sign of ignorance:

SET @ids = (SELECT ids FROM item_rel
    WHERE ids LIKE '1' OR ids LIKE '1,%' OR ids LIKE '%,1' OR ids LIKE '%,1,%') ;
SET @ids = (SELECT IF (@ids IS NOT NULL,@ids,'99999999999999999999999')) ;
SET @q = CONCAT('SELECT * FROM items WHERE ID IN (', @ids,')') ;
PREPARE stmt FROM @q ;
EXECUTE stmt ;

"99999999999999999999999" must be any value that never found in your db.