SQL加入MAX

Question

我有两个用于处理用户活动的表（serverlogdetail a，serverlogid b） 用户可以在一天内对不同的应用程序进行多次不同的登录（a.entrydate）（b.appname） 对于用户有权访问的所有应用程序，我需要返回上次登录时的列表。

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))

感谢提前

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))