mysql - SQL 选项存储和引用

Question

如果我有一张 table :

CREATE TABLE Kids (
    kid_id int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    kid_name varchar(45) NOT NULL,
    kid_favcolors (text) NULL,
    PRIMARY_KEY(kid_id)
    )

我有一张 table :

CREATE TABLE Colors (
    color_id int(10) UNSIGNED NOT NULL AUTO_INCREMENT,
    color_name varchar(45) NOT NULL,
    PRIMARY_KEY(color_id)
)

通过逗号分隔的 id 引用喜欢的颜色的行:

INSERT INTO Kids(kid_name, kid_favcolors) VALUES('Joe','1,2,3,4,5');
INSERT INTO Kids(kid_name, kid_favcolors) VALUES('Mary','1,2,3');

我将如何创建一个语句来返回 Kid 数据库中的每个条目以及 kid_favcolors 列中引用的所有 ID 的 Kid_name 和 color_name。

例如:

COLORS:

color_id    color_name
1           yellow
2           green
3           blue
4           purple
5           red
6           brown
7           black

KIDS:

kid_id      kid_name    kid_favcolors
1           Joe         1,2,3,4,5
2           Mary        1,2,3

and I want to retrieve

kid_id      kid_name    favorite_colors
1           Joe         yellow, green, blue, purple, red
2           Mary        yellow, green, blue

The queries are being executed on existing data and database structure. If there is no feasible solution, rearranging the structure of the data is possible but I assume would add a considerable amount of time to the solution. Either way, would like some help.

I am able to retrieve the colors from the database using:

SELECT STUFF((SELECT ', ' + color_name FROM colors WHERE color_id IN (1,2,3,4,5) FOR XML PATH('')),1, 2, '') AS colors

        colors
1       yellow, green, blue, purple, red

但是当我尝试更复杂的查询时，我似乎无法通过从 Kids 表中提取 ID 来找到合并上述语句的方法。

SELECT kids.kid_id, kids.kid_name, favorite_colors FROM kids JOIN colors ON colors.id IN kids.kid_favcolors as favorite_colors

虽然它看起来对我有用，但不起作用。不确定我离得远还是真的很近。

Answer 1

在原来的解决方案中，将CSV字符串存储在一个字段中违反了1NF；实际上——根据定义——该表甚至不符合关系。因此，在这种情况下，将字符串视为一个原子数据片段，并在应用层对其进行分解。

要在DB层解决，只需修复设计即可。