SQL code

SQL code Student(S#,Sname,Sage,Ssex) 学生表  Course(C#,Cname,T#) 课程表  SC(S#,C#,score) 成绩表  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 9、查询所有课程成绩小于60分的同学的学号、姓名；    select S#,Sname    from Student    where S# not in (select Student.S# from Student,SC where S.S#=SC.S# and score>60);  10、查询没有学全所有课的同学的学号、姓名；      select Student.S#,Student.Sname      from Student,SC      where Student.S#=SC.S# group by  Student.S#,Student.Sname having count(C#) <(select count(C#) from Course);  11、查询至少有一门课与学号为“1001”的同学所学相同的同学的学号和姓名；      select S#,Sname from Student,SC where Student.S#=SC.S# and C# in select C# from SC where S#='1001';  12、查询至少学过学号为“001”同学所有一门课的其他同学学号和姓名；      select distinct SC.S#,Sname      from Student,SC      where Student.S#=SC.S# and C# in (select C# from SC where S#='001');  13、把“SC”表中“叶平”老师教的课的成绩都更改为此课程的平均成绩；      update SC set score=(select avg(SC_2.score)      from SC SC_2      where SC_2.C#=SC.C# ) from Course,Teacher where Course.C#=SC.C# and Course.T#=Teacher.T# and Teacher.Tname='叶平');  14、查询和“1002”号的同学学习的课程完全相同的其他同学学号和姓名；      select S# from SC where C# in (select C# from SC where S#='1002')      group by S# having count(*)=(select count(*) from SC where S#='1002');  15、删除学习“叶平”老师课的SC表记录；      Delect SC      from course ,Teacher       where Course.C#=SC.C# and Course.T#= Teacher.T# and Tname='叶平';  16、向SC表中插入一些记录，这些记录要求符合以下条件：没有上过编号“003”课程的同学学号、2、      号课的平均成绩；      Insert SC select S#,'002',(Select avg(score)      from SC where C#='002') from Student where S# not in (Select S# from SC where C#='002');  17、按平均成绩从高到低显示所有学生的“数据库”、“企业管理”、“英语”三门的课程成绩，按如下形式显示： 学生ID,,数据库,企业管理,英语,有效课程数,有效平均分      SELECT S# as 学生ID          ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='004') AS 数据库          ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='001') AS 企业管理          ,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='006') AS 英语          ,COUNT(*) AS 有效课程数, AVG(t.score) AS 平均成绩      FROM SC AS t      GROUP BY S#      ORDER BY avg(t.score)   18、查询各科成绩最高和最低的分：以如下形式显示：课程ID，最高分，最低分      SELECT L.C# As 课程ID,L.score AS 最高分,R.score AS 最低分      FROM SC L ,SC AS R      WHERE L.C# = R.C# and          L.score = (SELECT MAX(IL.score)                        FROM SC AS IL,Student AS IM                        WHERE L.C# = IL.C# and IM.S#=IL.S#                        GROUP BY IL.C#)          AND          R.Score = (SELECT MIN(IR.score)                        FROM SC AS IR                        WHERE R.C# = IR.C#                    GROUP BY IR.C#                      );  19、按各科平均成绩从低到高和及格率的百分数从高到低顺序      SELECT t.C# AS 课程号,max(course.Cname)AS 课程名,isnull(AVG(score),0) AS 平均成绩          ,100 * SUM(CASE WHEN  isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数      FROM SC T,Course      where t.C#=course.C#      GROUP BY t.C#      ORDER BY 100 * SUM(CASE WHEN  isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC  20、查询如下课程平均成绩和及格率的百分数(用"1行"显示): 企业管理（001），马克思（002），OO&UML （003），数据库（004）      SELECT SUM(CASE WHEN C# ='001' THEN score ELSE 0 END)/SUM(CASE C# WHEN '001' THEN 1 ELSE 0 END) AS 企业管理平均分          ,100 * SUM(CASE WHEN C# = '001' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '001' THEN 1 ELSE 0 END) AS 企业管理及格百分数          ,SUM(CASE WHEN C# = '002' THEN score ELSE 0 END)/SUM(CASE C# WHEN '002' THEN 1 ELSE 0 END) AS 马克思平均分          ,100 * SUM(CASE WHEN C# = '002' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '002' THEN 1 ELSE 0 END) AS 马克思及格百分数          ,SUM(CASE WHEN C# = '003' THEN score ELSE 0 END)/SUM(CASE C# WHEN '003' THEN 1 ELSE 0 END) AS UML平均分          ,100 * SUM(CASE WHEN C# = '003' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '003' THEN 1 ELSE 0 END) AS UML及格百分数          ,SUM(CASE WHEN C# = '004' THEN score ELSE 0 END)/SUM(CASE C# WHEN '004' THEN 1 ELSE 0 END) AS 数据库平均分          ,100 * SUM(CASE WHEN C# = '004' AND score >= 60 THEN 1 ELSE 0 END)/SUM(CASE WHEN C# = '004' THEN 1 ELSE 0 END) AS 数据库及格百分数    FROM SC