sql查询实例1（学生表_课程表_成绩表_教师表）
【摘要】 表架构
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
建表语句
CREATE TABLE student ( s# INT, sname nvarchar(32), ...
表架构
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
建表语句
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CREATE TABLE student
-
(
-
s# INT,
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sname nvarchar(32),
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sage INT,
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ssex nvarchar(8)
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)
-
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CREATE TABLE course
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(
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c# INT,
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cname nvarchar(32),
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t# INT
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)
-
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CREATE TABLE sc
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(
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s# INT,
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c# INT,
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score INT
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)
-
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CREATE TABLE teacher
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(
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t# INT,
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tname nvarchar(16)
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)
插入测试数据语句
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insert into Student select 1,N'刘一',18,N'男' union all
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select 2,N'钱二',19,N'女' union all
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select 3,N'张三',17,N'男' union all
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select 4,N'李四',18,N'女' union all
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select 5,N'王五',17,N'男' union all
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select 6,N'赵六',19,N'女'
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insert into Teacher select 1,N'叶平' union all
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select 2,N'贺高' union all
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select 3,N'杨艳' union all
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select 4,N'周磊'
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insert into Course select 1,N'语文',1 union all
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select 2,N'数学',2 union all
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select 3,N'英语',3 union all
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select 4,N'物理',4
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insert into SC
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select 1,1,56 union all
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select 1,2,78 union all
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select 1,3,67 union all
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select 1,4,58 union all
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select 2,1,79 union all
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select 2,2,81 union all
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select 2,3,92 union all
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select 2,4,68 union all
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select 3,1,91 union all
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select 3,2,47 union all
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select 3,3,88 union all
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select 3,4,56 union all
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select 4,2,88 union all
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select 4,3,90 union all
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select 4,4,93 union all
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select 5,1,46 union all
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select 5,3,78 union all
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select 5,4,53 union all
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select 6,1,35 union all
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select 6,2,68 union all
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select 6,4,71
问题
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问题：
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1、查询“001”课程比“002”课程成绩高的所有学生的学号；
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select a.S# from (select s#,score from SC where C#='001') a,(select s#,score
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from SC where C#='002') b
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where a.score>b.score and a.s#=b.s#;
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2、查询平均成绩大于60分的同学的学号和平均成绩；
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select S#,avg(score)
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from sc
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group by S# having avg(score) >60;
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3、查询所有同学的学号、姓名、选课数、总成绩；
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select Student.S#,Student.Sname,count(SC.C#),sum(score)
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from Student left Outer join SC on Student.S#=SC.S#
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group by Student.S#,Sname
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4、查询姓“李”的老师的个数；
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select count(distinct(Tname))
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from Teacher
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where Tname like '李%';
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5、查询没学过“叶平”老师课的同学的学号、姓名；
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select Student.S#,Student.Sname
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from Student
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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');
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6、查询学过“001”并且也学过编号“002”课程的同学的学号、姓名；
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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');
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7、查询学过“叶平”老师所教的所有课的同学的学号、姓名；
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select S#,Sname
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from Student
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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'));
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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；
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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
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from Student,SC where Student.S#=SC.S# and C#='001') S_2 where score2 <score;
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9、查询所有课程成绩小于60分的同学的学号、姓名；
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select S#,Sname
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from Student
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where S# not in (select S.S# from Student AS S,SC where S.S#=SC.S# and score>60);
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10、查询没有学全所有课的同学的学号、姓名；
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select Student.S#,Student.Sname
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from Student,SC
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where Student.S#=SC.S# group by Student.S#,Student.Sname having count(C#) <(select count(C#) from Course);
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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；
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select distinct S#,Sname from Student,SC where Student.S#=SC.S# and SC.C# in (select C# from SC where S#='1001');
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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；
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select distinct SC.S#,Sname
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from Student,SC
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where Student.S#=SC.S# and C# in (select C# from SC where S#='001');
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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；
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update SC set score=(select avg(SC_2.score)
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from SC SC_2
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where SC_2.C#=SC.C# ) from Course,Teacher where Course.C#=SC.C# and Course.T#=Teacher.T# and Teacher.Tname='叶平');
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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；
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select S# from SC where C# in (select C# from SC where S#='1002')
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group by S# having count(*)=(select count(*) from SC where S#='1002');
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15、删除学习“叶平”老师课的SC表记录；
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Delect SC
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from course ,Teacher
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where Course.C#=SC.C# and Course.T#= Teacher.T# and Tname='叶平';
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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、
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号课的平均成绩；
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Insert SC select S#,'002',(Select avg(score)
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from SC where C#='002') from Student where S# not in (Select S# from SC where C#='002');
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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
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SELECT S# as 学生ID
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,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='004') AS 数据库
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,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='001') AS 企业管理
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,(SELECT score FROM SC WHERE SC.S#=t.S# AND C#='006') AS 英语
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,COUNT(*) AS 有效课程数, AVG(t.score) AS 平均成绩
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FROM SC AS t
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GROUP BY S#
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ORDER BY avg(t.score)
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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
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SELECT L.C# As 课程ID,L.score AS 最高分,R.score AS 最低分
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FROM SC L ,SC AS R
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WHERE L.C# = R.C# and
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L.score = (SELECT MAX(IL.score)
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FROM SC AS IL,Student AS IM
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WHERE L.C# = IL.C# and IM.S#=IL.S#
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GROUP BY IL.C#)
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AND
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R.Score = (SELECT MIN(IR.score)
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FROM SC AS IR
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WHERE R.C# = IR.C#
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GROUP BY IR.C#
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);
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自己写的:select c# ,max(score)as 最高分 ,min(score) as 最低分 from dbo.sc group by c#
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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
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SELECT t.C# AS 课程号,max(course.Cname)AS 课程名,isnull(AVG(score),0) AS 平均成绩
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,100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) AS 及格百分数
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FROM SC T,Course
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where t.C#=course.C#
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GROUP BY t.C#
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ORDER BY 100 * SUM(CASE WHEN isnull(score,0)>=60 THEN 1 ELSE 0 END)/COUNT(*) DESC
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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）
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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
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,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
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,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
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,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
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,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
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,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
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,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
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,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
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FROM SC
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21、查询不同老师所教不同课程平均分从高到低显示
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SELECT max(Z.T#) AS 教师ID,MAX(Z.Tname) AS 教师姓名,C.C# AS 课程ＩＤ,MAX(C.Cname) AS 课程名称,AVG(Score) AS 平均成绩
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FROM SC AS T,Course AS C ,Teacher AS Z
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where T.C#=C.C# and C.T#=Z.T#
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GROUP BY C.C#
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ORDER BY AVG(Score) DESC
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22、查询如下课程成绩第 3 名到第 6 名的学生成绩单：企业管理（001），马克思（002），UML （003），数据库（004）
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[学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩
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SELECT DISTINCT top 3
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SC.S# As 学生学号,
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Student.Sname AS 学生姓名 ,
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T1.score AS 企业管理,
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T2.score AS 马克思,
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T3.score AS UML,
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T4.score AS 数据库,
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ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) as 总分
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FROM Student,SC LEFT JOIN SC AS T1
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ON SC.S# = T1.S# AND T1.C# = '001'
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LEFT JOIN SC AS T2
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ON SC.S# = T2.S# AND T2.C# = '002'
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LEFT JOIN SC AS T3
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ON SC.S# = T3.S# AND T3.C# = '003'
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LEFT JOIN SC AS T4
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ON SC.S# = T4.S# AND T4.C# = '004'
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WHERE student.S#=SC.S# and
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ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0)
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NOT IN
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(SELECT
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DISTINCT
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TOP 15 WITH TIES
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ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0)
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FROM sc
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LEFT JOIN sc AS T1
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ON sc.S# = T1.S# AND T1.C# = 'k1'
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LEFT JOIN sc AS T2
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ON sc.S# = T2.S# AND T2.C# = 'k2'
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LEFT JOIN sc AS T3
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ON sc.S# = T3.S# AND T3.C# = 'k3'
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LEFT JOIN sc AS T4
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ON sc.S# = T4.S# AND T4.C# = 'k4'
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ORDER BY ISNULL(T1.score,0) + ISNULL(T2.score,0) + ISNULL(T3.score,0) + ISNULL(T4.score,0) DESC);
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23、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60]
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SELECT SC.C# as 课程ID, Cname as 课程名称
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,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85]
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,SUM(CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 - 70]
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,SUM(CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 - 60]
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,SUM(CASE WHEN score < 60 THEN 1 ELSE 0 END) AS [60 -]
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FROM SC,Course
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where SC.C#=Course.C#
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GROUP BY SC.C#,Cname;
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24、查询学生平均成绩及其名次
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SELECT 1+(SELECT COUNT( distinct 平均成绩)
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FROM (SELECT S#,AVG(score) AS 平均成绩
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FROM SC
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GROUP BY S#
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) AS T1
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WHERE 平均成绩 > T2.平均成绩) as 名次,
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S# as 学生学号,平均成绩
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FROM (SELECT S#,AVG(score) 平均成绩
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FROM SC
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GROUP BY S#
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) AS T2
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ORDER BY 平均成绩 desc;
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25、查询各科成绩前三名的记录:(不考虑成绩并列情况)
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SELECT t1.S# as 学生ID,t1.C# as 课程ID,Score as 分数
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FROM SC t1
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WHERE score IN (SELECT TOP 3 score
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FROM SC
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WHERE t1.C#= C#
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ORDER BY score DESC
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)
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ORDER BY t1.C#;
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26、查询每门课程被选修的学生数
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select c#,count(S#) from sc group by C#;
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27、查询出只选修了一门课程的全部学生的学号和姓名
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select SC.S#,Student.Sname,count(C#) AS 选课数
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from SC ,Student
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where SC.S#=Student.S# group by SC.S# ,Student.Sname having count(C#)=1;
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28、查询男生、女生人数
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Select count(Ssex) as 男生人数 from Student group by Ssex having Ssex='男';
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Select count(Ssex) as 女生人数 from Student group by Ssex having Ssex='女'；
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29、查询姓“张”的学生名单
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SELECT Sname FROM Student WHERE Sname like '张%';
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30、查询同名同性学生名单，并统计同名人数
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select Sname,count(*) from Student group by Sname having count(*)>1;;
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31、1981年出生的学生名单(注：Student表中Sage列的类型是datetime)
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select Sname, CONVERT(char (11),DATEPART(year,Sage)) as age
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from student
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where CONVERT(char(11),DATEPART(year,Sage))='1981';
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32、查询每门课程的平均成绩，结果按平均成绩升序排列，平均成绩相同时，按课程号降序排列
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Select C#,Avg(score) from SC group by C# order by Avg(score),C# DESC ;
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33、查询平均成绩大于85的所有学生的学号、姓名和平均成绩
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select Sname,SC.S# ,avg(score)
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from Student,SC
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where Student.S#=SC.S# group by SC.S#,Sname having avg(score)>85;
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34、查询课程名称为“数据库”，且分数低于60的学生姓名和分数
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Select Sname,isnull(score,0)
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from Student,SC,Course
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where SC.S#=Student.S# and SC.C#=Course.C# and Course.Cname='数据库'and score <60;
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35、查询所有学生的选课情况；
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SELECT SC.S#,SC.C#,Sname,Cname
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FROM SC,Student,Course
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where SC.S#=Student.S# and SC.C#=Course.C# ;
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36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数；
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SELECT distinct student.S#,student.Sname,SC.C#,SC.score
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FROM student,Sc
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WHERE SC.score>=70 AND SC.S#=student.S#;
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37、查询不及格的课程，并按课程号从大到小排列
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select c# from sc where scor e <60 order by C# ;
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38、查询课程编号为003且课程成绩在80分以上的学生的学号和姓名；
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select SC.S#,Student.Sname from SC,Student where SC.S#=Student.S# and Score>80 and C#='003';
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39、求选了课程的学生人数
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select count(*) from sc;
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40、查询选修“叶平”老师所授课程的学生中，成绩最高的学生姓名及其成绩
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select Student.Sname,score
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from Student,SC,Course C,Teacher
-
where Student.S#=SC.S# and SC.C#=C.C# and C.T#=Teacher.T# and Teacher.Tname='叶平' and SC.score=(select max(score)from SC where C#=C.C# );
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41、查询各个课程及相应的选修人数
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select count(*) from sc group by C#;
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42、查询不同课程成绩相同的学生的学号、课程号、学生成绩
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select distinct A.S#,B.score from SC A ,SC B where A.Score=B.Score and A.C# <>B.C# ;
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43、查询每门功成绩最好的前两名
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SELECT t1.S# as 学生ID,t1.C# as 课程ID,Score as 分数
-
FROM SC t1
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WHERE score IN (SELECT TOP 2 score
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FROM SC
-
WHERE t1.C#= C#
-
ORDER BY score DESC
-
)
-
ORDER BY t1.C#;
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44、统计每门课程的学生选修人数（超过10人的课程才统计）。要求输出课程号和选修人数，查询结果按人数降序排列，查询结果按人数降序排列，若人数相同，按课程号升序排列
-
select C# as 课程号,count(*) as 人数
-
from sc
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group by C#
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order by count(*) desc,c#
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45、检索至少选修两门课程的学生学号
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select S#
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from sc
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group by s#
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having count(*) > = 2
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46、查询全部学生都选修的课程的课程号和课程名
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select C#,Cname
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from Course
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where C# in (select c# from sc group by c#)
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47、查询没学过“叶平”老师讲授的任一门课程的学生姓名
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select Sname from Student where S# not in (select S# from Course,Teacher,SC where Course.T#=Teacher.T# and SC.C#=course.C# and Tname='叶平');
-
48、查询两门以上不及格课程的同学的学号及其平均成绩
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select S#,avg(isnull(score,0)) from SC where S# in (select S# from SC where score <60 group by S# having count(*)>2)group by S#;
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49、检索“004”课程分数小于60，按分数降序排列的同学学号
-
select S# from SC where C#='004'and score <60 order by score desc;
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50、删除“002”同学的“001”课程的成绩
-
delete from Sc where S#='001'and C#='001';
文章来源: fantianzuo.blog.csdn.net，作者：兔老大RabbitMQ，版权归原作者所有，如需转载，请联系作者。
原文链接：fantianzuo.blog.csdn.net/article/details/103430105
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