某硕笔试题mysql数据库部分（较为全面）
时间：2021-07-01 10:21:17
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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；
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
<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,Course
where 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 Student
group 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
