来看看大家怎么做这道SQL题

[codearts]

不小心到DB2版找到的这道题：

阿里baba的面试题

有三个表
学生表 S
SID SNAME
教师课表 T
TID TNAME TCL
成绩表 SC
SID TCL SCR
各字段的含义不用我标明了吧，大侠哥哥么！呵呵

现在要求写SQL查询
1、选修了A、B课程，并且A课程的成绩大于B成绩的学生姓名？

[codearts]

写一下这道题，可以看出一个人的SQL功力。

猩猩们都来写一下

[huxingz]

SELECT SNAME
FROM S, SC T1, SC T2
WHERE S.SID = T1.SID
AND S.SID = T2.SID
AND T1.TCL = 'A'
AND T2.TCL = 'B'
AND T1.SCR > T2.SCR

[luoyoumou]

SELECT s.sname
FROM s
WHERE EXISTS (SELECT sc1.sid, sc2.sid
	       FROM sc sc1 INNSER JOIN sc sc2 ON sc1.sid=sc2.sid AND sc1.tcl='A' AND sc2.tcl='B' AND sc1.scr>sc2.scr
	       WHERE sc1.sid=s.sid );

[luoyoumou]

-- inner写错了！
SELECT s.sname
FROM s
WHERE EXISTS (SELECT sc1.sid, sc2.sid
	       FROM sc sc1 INNER JOIN sc sc2 ON sc1.sid=sc2.sid AND sc1.tcl='A' AND sc2.tcl='B' AND sc1.scr>sc2.scr
	       WHERE sc1.sid=s.sid );

[luoyoumou]

-- 功力不怎么样：不知道写对了没有？
-- 写错了，就当是我瞎写的！

[tangren]

--1
with s as(
  select '001' sid,'张三' sname from dual union all  
  select '002' sid,'李四' sname from dual union all
  select '003' sid,'王五' sname from dual), sc as (
  select '001' sid,'A' tcl, 80 scr from dual union all
  select '001' sid,'B' tcl, 70 scr from dual union all
  select '002' sid,'A' tcl, 60 scr from dual union all
  select '002' sid,'B' tcl, 80 scr from dual union all
  select '003' sid,'A' tcl, 80 scr from dual union all
  select '003' sid,'C' tcl, 80 scr from dual)
    
  SELECT s.*
    FROM s,
         (SELECT a.sid
            FROM (SELECT * FROM sc WHERE tcl = 'A') a, (SELECT * FROM sc WHERE tcl = 'B') b
           WHERE a.sid = b.sid AND
                 a.scr > b.scr) t
   WHERE s.sid = t.sid

--2
with s as(
  select '001' sid,'张三' sname from dual union all  
  select '002' sid,'李四' sname from dual union all
  select '003' sid,'王五' sname from dual), sc as (
  select '001' sid,'A' tcl, 80 scr from dual union all
  select '001' sid,'B' tcl, 70 scr from dual union all
  select '002' sid,'A' tcl, 60 scr from dual union all
  select '002' sid,'B' tcl, 80 scr from dual union all
  select '003' sid,'A' tcl, 80 scr from dual union all
  select '003' sid,'C' tcl, 80 scr from dual)
SELECT *
  FROM s
 WHERE sid IN (SELECT sid
                 FROM sc a
                WHERE EXISTS (SELECT 1
                         FROM sc b
                        WHERE b.sid = a.sid AND
                              a.tcl = 'A' AND
                              b.tcl = 'B' AND
                              a.scr > b.scr))

[jy03070017]

貌似教师课表没啥用。。

[cyousor]

With 
s As
(select '1' sid, 'A' sname From dual
Union All  select '2' sid, 'B' sname From dual
Union All  select '3', 'C' From dual
Union All  select '4', 'D' From dual
),sc As
(Select '1' sid, 'A' tcl, 90 scr From dual
Union All Select '1', 'B', 91 From dual
Union All Select '2', 'B', 91 From dual
Union All Select '2', 'A', 90 From dual
Union All Select '3', 'A', 91 From dual
Union All Select '3', 'B', 51 From dual
Union All Select '4', 'A', 61 From dual
)
select t1.sid,s.sname From (
Select sid,scr, sign(scr - nvl(lead(scr)over(Partition By sid Order By tcl),scr)) si From sc
) t1, s 
Where t1.si = 1
And t1.sid = s.sid

[心中的彩虹]

select sname from s where sid in(select a.sid
from sc a,sc b
where a.sid=b.sid and a.tcl='A' and b.tcl='B' and a.scr>b.scr) 

[cyousor]

With 
s As
(select '1' sid, 'A' sname From dual
Union All  select '2' sid, 'B' sname From dual
Union All  select '3', 'C' From dual
Union All  select '4', 'D' From dual
),sc As
(Select '1' sid, 'A' tcl, 90 scr From dual
Union All Select '1', 'B', 91 From dual
Union All Select '2', 'B', 91 From dual
Union All Select '2', 'A', 90 From dual
Union All Select '3', 'A', 91 From dual
Union All Select '3', 'B', 51 From dual
Union All Select '4', 'A', 61 From dual
)
select t1.sid,s.sname From (
Select sid,scr, sign(scr - nvl(lead(scr)over(Partition By sid Order By tcl),scr)) si From sc
Where tcl = 'A' Or tcl = 'B') t1, s 
Where t1.si = 1
And t1.sid = s.sid

哦，应该加上一个条件，

[木子0204]

高手！！！！！！！！！！！！

[summer123428316]

我看看看,才知道自己老菜了..唉