I've two tables : DISH and DISH_HAS_DISHES. Dish table has all of the dishes and "Dish_has_dishes" table includes a one-to-many relationship with "Dish" table. I.e. a dish might have multiple dishes. For instance

DISH :

dish_id   dish_name
1         dish_1
2         dish_2
3         dish_3
4         dish_4

DISH_HAS_DISHES :

meal_id   dish_id
1         2
1         3
1         4

Here meal_id and dish_id both of them are IDs from DISH table. Now I would like a format such as this:

meal_id     dish_ids     dish_names
1           2,3,4        dish_2, dish_3, dish_4

That's comma separated dish id and names for every meal. How to achieve that?

Use GROUP_CONCAT FUNCTION

http://dev.mysql.com/tech-resources/articles/4.1/grab-bag.html

 SELEct m.meal_Id, 
        GROUP_CONCAT(dish_id) dish_ids, 
        GROUP_CONCAT(dish_name) dish_names
 FROM DISH_HAS_DISHES m JOIN DISH d ON (m.dish_id = d.dish_id)
 GROUP BY meal_Id