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简单举例:
SQL> desc test4
Name Null? Type
----------------------------------------- -------- ----------------------------
NAME VARCHAR2(20)
EXPERT VARCHAR2(20)
R_DATE DATE
SQL> select * from test4
2 /
NAME EXPERT R_DATE
-------------------- -------------------- -------------------
sh huang 2006-09-29 08:10:44
an li 2006-09-29 08:11:00
sh huang 2006-09-29 08:11:04
an li 2006-09-29 08:11:08
sh huang 2006-09-29 08:11:12
an li 2006-09-29 08:11:15
sh huang 2006-09-29 08:11:19
an li 2006-09-29 08:11:22
8 rows selected.
SQL> l
1 select name,expert,r_date from
2 (select name,expert,r_date from
3 (select ta.name,ta.expert,ta.r_date from test4 ta,
4 (select name,expert,rownum t_num from
5 (select name,expert from test4 order by r_date desc)
6 where rownum<3) tb
7 where ta.expert=tb.expert and tb.t_num=2)
8 order by r_date desc
9 )
10* where rownum<3
result:
NAME EXPERT R_DATE
-------------------- -------------------- -------------------
sh huang 2006-09-29 08:11:19
sh huang 2006-09-29 08:11:12 |
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