MySQL:多行作为逗号分隔的单行

问题描述

我有两个表:DISH 和 DISH_HAS_DISHES.Dish 表包含所有菜肴，Dish_has_dishes"表与Dish"表是一对多的关系.IE.一道菜可以有多道菜.例如

I have two tables : DISH and DISH_HAS_DISHES. Dish table has all the dishes and "Dish_has_dishes" table has a one-to-many relationship with "Dish" table. I.e. a dish can have multiple dishes. For example

菜:

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

这里的meal_id和dish_id都是DISH表中的ID.现在我想要这样的格式:

Here meal_id and dish_id both are IDs from DISH table. Now I want a format like this:

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

那是每顿饭用逗号分隔的菜名和菜名.怎么做?

That is comma separated dish id and names for each meal. How to do that?

推荐答案

使用 GROUP_CONCAT FUNCTION

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

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