SQL與MAX一起加入

Question

我有兩張表（serverlogdetail a，serverlogid b），用於處理用戶活動 用戶可以在不同的應用程序中使用不同的日誌（a.entrydate） 對於所有到一個用戶具有訪問權限的應用程序，我需要與上次他/她登錄返回一個列表。

SELECT b.appname ,max(to_char(a.entrydate)), a.username, a.msgnumber 
    FROM serverlogdetail a, serverlogid b 

    WHERE a.msgnumber = 1020055 
    AND A.entrydate BETWEEN (SYSDATE-90) AND SYSDATE 

GROUP BY b.appname, a.dbname, a.username,a.msgnumber, a.entrydate 
ORDER BY b.appname, max(to_char(a.entrydate)) 

在此先感謝

Answer 1

SELECT b.appname , a.username, a.msgnumber, max(to_char(a.entrydate)) 
FROM serverlogdetail a, serverlogid b 

WHERE a.msgnumber = 1020055 
AND A.entrydate BETWEEN (SYSDATE-90) AND SYSDATE 
AND A.something = B.something   -- the condition you're missing!!! 

GROUP BY b.appname, a.username, a.msgnumber 
ORDER BY b.appname, max(to_char(a.entrydate))