mysql查询语句练习总结(涵盖所有sql语法)_mysql查询练习

最近在学习SQL嘛,所以各个地方找题目来练手,毕竟现在能离得开数据库么?
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#; 
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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；

 select S#,avg(score) 
    from sc 
    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；

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 
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4、查询姓“李”的老师的个数；

select count(distinct(Tname)) 
  from Teacher 
  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；

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'); 
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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；

 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；

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')); 
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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；

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 <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；

select S#,Sname 
  from Student 
  where S# not in (select Student.S# from Student,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；

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); 
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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；

select S#,Sname from Student,SC where Student.S#=SC.S# and 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；

select distinct SC.S#,Sname 
    from Student,SC 
    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；

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'); 
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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；

    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');
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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'; 
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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、
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');
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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

    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)  
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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

    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# 
                    ); 
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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

    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 
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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）

    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 
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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

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
	
FROM
	SC AS T,
	Course AS C,
	Teacher AS Z 
WHERE
	T.C #=C.C# and C.T#=Z.T#
	
GROUP BY
	C.C #
	
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）
[学生ID],[学生姓名],企业管理,马克思,UML,数据库,平均成绩

SELECT DISTINCT
	top 3 SC.S # As 学生学号,
	Student.Sname AS 学生姓名,
	T1.score AS 企业管理,
	T2.score AS 马克思,
	T3.score AS UML,
	T4.score AS 数据库,
	ISNULL( T1.score, 0 ) + ISNULL( T2.score, 0 ) + ISNULL( T3.score, 0 ) + ISNULL( T4.score, 0 ) AS 总分 
FROM
	Student,
	SC
	LEFT JOIN SC AS T1 ON SC.S # = T1.S# AND T1.C# = '001'
	LEFT JOIN SC AS T2 ON SC.S # = T2.S# AND T2.C# = '002'
	LEFT JOIN SC AS T3 ON SC.S # =T3.S# AND T3.C# = '003'
	LEFT JOIN SC AS T4 ON SC.S # = T4.S# AND T4.C# = '004'
	
WHERE
	student.S #=SC.S# and
	ISNULL( T1.score, 0 ) + ISNULL( T2.score, 0 ) + ISNULL( T3.score, 0 ) + ISNULL( T4.score, 0 ) NOT IN (
SELECT DISTINCT
		TOP 15 WITH TIES ISNULL( T1.score, 0 ) + ISNULL( T2.score, 0 ) + ISNULL( T3.score, 0 ) + ISNULL( T4.score, 0 ) 
	FROM
		sc
		LEFT JOIN sc AS T1 ON sc.S # = T1.S# AND T1.C#= 'k1'
		LEFT JOIN sc AS T2 ON sc.S # = T2.S# AND T2.C# = 'k2'
		LEFT JOIN sc AS T3 ON sc.S # = T3.S# AND T3.C# = 'k3'
		LEFT JOIN sc AS T4 ON sc.S # = T4.S# AND T4.C# = 'k4'
		
	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]

SELECT
	SC.C # as 课程ID, Cname
	AS 课程名称,
	SUM( CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END ) AS [ 100 - 85 ],
	SUM( CASE WHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END ) AS [ 85 - 70 ],
	SUM( CASE WHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END ) AS [ 70 - 60 ],
	SUM( CASE WHEN score < 60 THEN 1 ELSE 0 END ) AS [ 60 -] 
FROM
	SC,
	Coursewhere SC.C #=Course.C#
	
GROUP BY
	SC.C #,Cname;
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24、查询学生平均成绩及其名次

SELECT
	1+ ( SELECT COUNT( DISTINCT 平均成绩 ) FROM ( SELECT S #,AVG(score) AS 平均成绩
	FROM SC GROUP BY S #
	) AS T1 WHERE 平均成绩 > T2.平均成绩 ) AS 名次,
	S # as 学生学号,平均成绩
	
FROM
	( SELECT S #,AVG(score) 平均成绩
	FROM SC GROUP BY S #
) AS T2 
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)

SELECT
	t1.S # as 学生ID,t1.C# as 课程ID,Score as 分数
	
FROM
	SC t1 
WHERE
	score IN ( SELECT TOP 3 score FROM SC WHERE t1.C #= C#     ORDER BY score DESC
	) 
ORDER BY
t1.C #; 
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26、查询每门课程被选修的学生数

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

SELECT
	SC.S #,Student.Sname,count(C#) AS 选课数
	
FROM
	SC,
	Student 
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

Select count(Ssex) as 男生人数 from Student group by Ssex having Ssex='男'; 
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

  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

 select Sname,count(*) from Studentgroup 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)

select Sname,  CONVERT(char (11),DATEPART(year,Sage)) as age 
from student 
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

 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

select Sname,SC.S# ,avg(score) 
from Student,SC 
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

Select Sname,isnull(score,0) 
from Student,SC,Course 
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；

SELECT SC.S#,SC.C#,Sname,Cname 
FROM SC,Student,Course 
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；

 SELECT  distinct student.S#,student.Sname,SC.C#,SC.score 
    FROM student,Sc 
    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

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；

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

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

    select Student.Sname,score 
    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

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

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

 SELECT t1.S# as 学生ID,t1.C# as 课程ID,Score as 分数 
      FROM SC t1 
      WHERE score IN (SELECT TOP 2 score 
              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  
    group  by  C# 
    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

 select  S#  
    from  sc  
    group  by  s# 
    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

select  C#,Cname  
from  Course  
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

 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'); 
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48、查询两门以上不及格课程的同学的学号及其平均成绩

    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';
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