I know this is not a good practice of creating a table, so please let those thing aside first.

I have a table, let say table A and table B

```
Table A :
| ID | fk_tableB_ID | title
-------------------------
| 10 | 1,2          | title 1
| 11 | 3            | title 2

Table B :
| ID | category
---------------
| 1  | cat1
| 2  | cat2
| 3  | cat3

```

I tried this query:

```
SELECT
    a.ID,
    a.title,
    (
        SELECT
            group_concat(b.category)
        FROM
            tableB B
        WHERE
            B.ID IN (a.fk_tableB_ID)
    ) as category
FROM
    tableA a

```

It return :

```
| ID | category  | title
-----------------------
| 10 | cat1      | title1
| 11 | cat3      | title2            

```

But that's not what i want. What i want is 

```
| ID | category  | title
-----------------------
| 10 | cat1,cat2 | title1
| 11 | cat3      | title2

```

Please help, what is the correct mysql query code so i can get that table above.
Thx in advance