MySQL

Question

我有两个 table：

CREATE TABLE user (
    user_id INT PRIMARY KEY,
    ...
);
CREATE TABLE action (
    action_id INT PRIMARY KEY,
    user_id INT FOREIGN KEY REFERENCES user(user_id),
    action_type TINYINT,
    ...
);

每次用户执行特定操作时，都会在 action table 中插入一行。

现在我想找到所有执行过某组操作的所有用户。像这样：

SELECT user_id
FROM user, action
HAVING SET(action_type) INTERSECT (0,3,4,5) = (0,3,4,5);

当然，最后一行是我编造的。在 SQL 中有这样做的好方法吗？

Answer 1

`having 子句中的

4 是您集合中的动作数

SELECT u.user_id
FROM user u
JOIN action a on u.user_id = a.user_id
WHERE action_type IN (0,3,4,5)
GROUP BY u.user_id
HAVING count(distinct a.action_type) = 4

另一种方式是

SELECT u.user_id
FROM user u
JOIN action a on u.user_id = a.user_id
GROUP BY u.user_id
HAVING sum(a.action_type = 0) > 0
AND sum(a.action_type = 3) > 0
AND sum(a.action_type = 4) > 0
AND sum(a.action_type = 5) > 0

Answer 2

这是一个集内集查询的例子。我喜欢用 group by 和 having 来解决它们，因为这是一个非常灵活的方法：

SELECT user_id
FROM action a
WHERE action_type IN (0, 3, 4, 5)
GROUP BY user_id
HAVING COUNT(DISTINCT action_type) = 4;

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sql

set