找出10次考试中成绩连续下滑3次的学生

问题：从10次考试中，找出考试成绩连续下滑3次的学生姓名？

解法：

SQL> with tb as(
2 select 'aspen' sname,to_date('20100111','yyyymmdd')ttime,100 score from dual
3 union all
4 select 'aspen',to_date('20100211','yyyymmdd'),90 from dual
5 union all
6 select 'aspen',to_date('20100311','yyyymmdd'),80 from dual
7 union all
8 select 'aspen',to_date('20100411','yyyymmdd'),82 from dual
9 union all
10 select 'aspen',to_date('20100511','yyyymmdd'),81 from dual
11 union all
12 select 'aspen',to_date('20100611','yyyymmdd'),79 from dual
13 union all
14 select 'aspen',to_date('20100711','yyyymmdd'),77 from dual
15 union all
16 select 'aspen',to_date('20100811','yyyymmdd'),70 from dual
17 union all
18 select 'scott',to_date('20100111','yyyymmdd'),70 from dual
19 union all
20 select 'scott',to_date('20100211','yyyymmdd'),60 from dual
21 union all
22 select 'scott',to_date('20100311','yyyymmdd'),90 from dual
23 )
24 select distinct sname
25 from
26 (select sname,
27 ttime,
28 score,
29 row_number() over(partition by sname order by ttime) rn
30 from tb) t
31 where level>=4
32 start with rn=rn
33 connect by prior score>score and prior rn=rn-1
34 /

SNAME
-----
aspen

原帖：http://topic.csdn.net/u/20110314/15/5a7c8ca2-a0db-461c-b21b-07a74383341a.html?82160