WHERE子句中的MySQL CAST和LIKE

Question

I want to write following query in MySQL and keep getting errors. I have no idea what's wrong, everything seems fine by me.

Query:

SELECT 
    *
FROM 
    client
WHERE
    id IN (
        SELECT 
            client_id 
        FROM 
            url 
        WHERE 
            ',1,2,' LIKE '%,' + CAST(url_type_id AS CHAR(50)) + ',%'
        )

It must have got something to do with the "'%,' + " part, but I honestly don't get it

Answer 1

You have to use CONCAT() to join 2 strings not "+", here is the query which you looking for

SELECT *
FROM client
WHERE id IN ( SELECT client_id 
        FROM url 
        WHERE ',1,2,' LIKE CONCAT('%,', CAST(url_type_id AS CHAR(50)), ',%') 
)