在JOIN查询中使用Mysql GROUP_CONCAT

Question

I have a string resulting like this :

'41,42,43,44,45,46,'

from this query :

SELECT 
    GROUP_CONCAT(lv
        SEPARATOR ',') as Id
FROM
    (SELECT 
        @pv:=(SELECT 
                    GROUP_CONCAT(Id
                            SEPARATOR ',')
                FROM
                    iot_zone
                WHERE
                    FIND_IN_SET(id_zone, @pv)) AS lv
    FROM
        iot_zone
    JOIN (SELECT @pv:=40) tmp) a;

I need to join this result to a query like :

SELECT T.* FROM T, T2
WHERE T.Id = T2.Id

where T2 is a table with the result of GROUP_CONCAT

41
42
43
44
45
46

Can you help me ?

Many thanks

Answer 1

Try the following

CREATE TABLE T2(Id int);
INSERT T2(Id)VALUES(41),(42),(43);

SELECT *
FROM
  (
    SELECT '41,42,43,44,45,46,' Id
  ) T
JOIN T2 on CONCAT(',',T.Id) LIKE CONCAT('%,',T2.Id,',%')

I hope I understood your question correctly.

I found another variant with FIND_IN_SET - SELECT WHERE IN with GROUP_CONCAT as input

I think it'll be more useful

SELECT *
FROM
  (
    SELECT '41,42,43,44,45,46,' IdList
  ) T
JOIN T2 ON FIND_IN_SET(T2.Id,T.IdList)