mysql查询语句练习总结(涵盖所有sql语法)

￡神魔★判官ぃ 2024-03-17 16:36 56阅读 0赞

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#;

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；

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 <score;

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

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

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 
    );

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;

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;

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 #;

26、查询每门课程被选修的学生数

select c#,count(S#) from sc group by C#;

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;

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'；

29、查询姓“张”的学生名单

SELECT Sname FROM Student WHERE Sname like '张%';

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;;

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';

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 ;

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;

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;

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# ;

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#;

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# ;

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';

39、求选了课程的学生人数

select count(*) from sc;

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# );

41、查询各个课程及相应的选修人数

select count(*) from sc group by C#;

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# ;

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#;

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#

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

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#)

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');

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#;

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;