Mysql排名前2的事件查詢

Question

我正在開發使用MySQL和Visual Basic登錄/輸出表單。我現在的查詢只顯示每個用戶的最近事件，但我希望顯示前兩個事件（即：他/她何時登錄以及何時退出）

我有一個表event具有以下字段：

Event_ID 
User_BannerID 
Class_ID 
Timestamp  
Status  
Creator 

SELECT CONCAT(u.lastname, ', ', u.firstname) AS Name 
    , s.class AS Class 
    , DATE_FORMAT(e.timestamp,'%b %d %Y - %r') AS DateTime 
    , e.status AS Status     
FROM event e, user u, status s 
WHERE e.user_bannerid = u.user_bannerid 
    AND e.class_id = s.class_id 
    AND event_id IN 
    (
     SELECT MAX(event_id) 
     FROM event e 
     GROUP BY e.user_bannerid 
    ) 
ORDER BY name 

Answer 1

在SELECT句子使用LIMIT子句正確的順序組合BY：

SELECT ... 
FROM theTable 
WHERE ... 
LIMIT 2 
ORDER BY timestamp DESC 

Answer 2

看一看一節「選擇從每個組的頂部N行」在this article。

Answer 3

AND event_id IN 
(
    SELECT event_id 
    FROM (SELECT * FROM event ORDER BY event_id DESC LIMIT 2) e 
) 

變通辦法來源：http://forums.mysql.com/read.php?86,14788,14788及其答覆，鏈接在底部。測試在用mysql 5.2 5.1