使用MySQL JSON字段联接表 [英] Using MySQL JSON field to join on a table
问题描述
我有一个存储ID列表的json字段(我不知道这是最佳实践),我想知道是否可以在此JSON字段上使用do操作并在sql中使用它们.
I have a json field that stores a list of ids (not best practice here I know), I want to know if it's possible to use do operations on this JSON field and use them in the sql.
以下是我要实现的虚构示例,这样的事情可行吗?
Below is a fictitious example of what I'm trying to achieve, is something like this doable?
CREATE TABLE user (
user_id INT,
user_name VARCHAR(50),
user_groups JSON
);
CREATE TABLE user_group (
user_group_id INT,
group_name VARCHAR(50)
);
INSERT INTO user_group (user_group_id, group_name) VALUES (1, 'Group A');
INSERT INTO user_group (user_group_id, group_name) VALUES (2, 'Group B');
INSERT INTO user_group (user_group_id, group_name) VALUES (3, 'Group C');
INSERT INTO user (user_id, user_name, user_groups) VALUES (101, 'John', '[1,3]');
使用上述数据,我希望创建一个查询,使我得到如下结果:
With the above data I would like to fashion a query that gives me the results like this:
user_id | user_name | user_group_id | group_name|
-------------------------------------------------
101 | John | 1 | Group A
101 | John | 3 | Group C
下面我想一些伪风格的SQL,尽管我仍然不知道这是否可行,或者我将使用mysql提供的JSON函数实现这一目的
Some psuedo style SQL I'm thinking is below, though I still have no clue if this is possible, or what JSON functions mysql offers I would use to achieve this
SELECT
u.user_id,
u.user_name,
g.user_group_id
g.group_name
FROM users u
LEFT JOIN user_group g on g.user_group_id in some_json_function?(u.user_groups)
让我知道问题是否很清楚.
Let me know if the question isn't clear.
推荐答案
借助Feras的评论和一些摆弄:
With the help of Feras's comment and some fiddling:
SELECT
u.user_id,
u.user_name,
g.user_group_id,
g.group_name
FROM user u
LEFT JOIN user_group g on JSON_CONTAINS(u.user_groups, CAST(g.user_group_id as JSON), '$')
这似乎可行,请告诉我是否有更好的方法.
This appears to work, let me know if there's a better way.
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