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
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
;
50
、删除“
002
”同学的“
001
”课程的成绩
delete
from
Sc
where
S#
=
'
001
'
and
C#
=
'
001
'
;
