文件名称：MYSQL_MSS_ORACLE经典SQL
文件大小：1.09MB
文件格式：PDF
更新时间：2015-09-30 14:23:09
SQL
--Student(S#,Sname,Sage,Ssex) 学生表
--SC(S#,C#,score) 成绩表
--Course(C#,Cname,T#) 课程表
--Teacher(T#,Tname) 教师表
--问题：
1、--查询“001”课程比“002”课程成绩高的所有学生的学号；
select a.S# from (select s#,score from SC where C#='001') a,(select s#,score
from SC where C#='002') b
where a.score>b.score and a.s#=b.s#;
2、--查询平均成绩大于60分的同学的学号和平均成绩；
select S#,avg(score)
from sc
group by S# having avg(score) >60;
3、--查询所有同学的学号、姓名、选课数、总成绩；
select Student.S#,Student.Sname,count(SC.C#),sum(score)
from Student left Outer join SC on Student.S#=SC.S#
group by Student.S#,Sname
4、--查询姓“李”的老师的个数；
select count(distinct(Tname))
from Teacher
where Tname like '李%';
5、--查询没学过“叶平”老师课的同学的学号、姓名；
select Student.S#,Student.Sname
from Student
where S# not in (select distinct( SC.S#) from SC,Course,Teacher where
SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='叶平');
6、--查询学过“001”并且也学过编号“002”课程的同学的学号、姓名；
select Student.S#,Student.Sname from Student,SC where Student.S#=SC.S# and SC.C#='001'
and exists( Select * from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#='002');
7、--查询学过“叶平”老师所教的所有课的同学的学号、姓名；
select S#,Sname
from Student
where S# in (select S# from SC ,Course ,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T#
and Teacher.Tname='叶平' group by S# having count(SC.C#)=(select count(C#) from Course,Teacher
where Teacher.T#=Course.T# and Tname='叶平'));
8、--查询课程编号“002”的成绩比课程编号“001”课程低的所有同学的学号、姓名；
Select S#,Sname from (select Student.S#,Student.Sname,score ,(select score from SC SC_2 where
SC_2.S#=Student.S# and SC_2.C#='002') score2
from Student,SC where Student.S#=SC.S# and C#='001') S_2 where score2