php - PHP MySQL查询以获取特定用户ID的最大事件ID

Question

我有一个带有event_id, eventname, date, time, location,的表user_id。每个用户 ID 可以有多个事件 ID。例如，我想查询最高的事件 ID user id = 30。如何才能做到这一点？

Answer 1

SELECT 
    MAX(event_id) as MEvent_id , 
    eventname, 
    date, 
    time, 
    location, 
    user_id 
FROM mytable 
WHERE user_id = 30

Answer 2

这非常简单。

 SELECT MAX(event_id) FROM table WHERE user_id = 30

Answer 3

SELECT  a.*
FROM    tableName a
        INNER JOIN
        (
            SELECT userID, MAX(event_ID) maxID
            FROM tableName
            GROUP BY userID
        ) b ON  a.userID = b.userID AND
                a.event_ID = b.maxID
WHERE   a.userID = 30