请教一个GROUP 函数的问题！

Question

SQL> select sbtime from records where to_char(sbtime,'yyyymm')=to_char(sysdate,'yyyymm');SBTIME
-----------------
02-12-02 08:25:10
02-12-02 08:25:26
02-12-02 08:26:33
02-12-02 14:57:19
03-12-02 08:05:46
03-12-02 08:16:20
03-12-02 08:20:24
04-12-02 08:08:36
04-12-02 08:21:04
04-12-02 08:23:48
05-12-02 08:12:07SBTIME
-----------------
05-12-02 08:19:18
05-12-02 08:20:03
06-12-02 08:07:51
06-12-02 08:14:51
06-12-02 08:17:39
09-12-02 08:16:02
09-12-02 08:16:14
09-12-02 08:16:19
09-12-02 08:26:02
10-12-02 08:09:59
10-12-02 08:09:59SBTIME
-----------------
10-12-02 08:16:20
10-12-02 08:26:13
11-12-02 08:16:51
11-12-02 08:19:37
11-12-02 08:24:28已选择27行。SQL> select max(sbtime) from records where to_char(sbtime,'yyyymm')=to_char(sysdate,'yyyymm') group 
by employeeno;MAX(SBTIME)
-----------------
11-12-02 08:24:28
11-12-02 08:19:37
02-12-02 14:57:19
11-12-02 08:16:51
10-12-02 08:09:59

Answer 1

select a,max(b) from tname where ...  group by a;