本文转自:http://topic.csdn.net/u/20100517/17/B2AB9D5E-73A2-4F54-A7EC-40A5EABD8621.html
SQL code
/*
标题:一个项目涉及到的50个Sql语句(整理版) 作者:爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开) 时间:2010-05-10 地点:重庆航天职业学院 说明:以下五十个语句都按照测试数据进行过测试,最好每次只单独运行一个语句。 问题及描述: --1.学生表 Student(S#,Sname,Sage,Ssex) --S# 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别 --2.课程表 Course(C#,Cname,T#) --C# --课程编号,Cname 课程名称,T# 教师编号 --3.教师表 Teacher(T#,Tname) --T# 教师编号,Tname 教师姓名 --4.成绩表 SC(S#,C#,score) --S# 学生编号,C# 课程编号,score 分数
*/
--
创建测试数据
create
table
Student(S#
varchar
(
10
),Sname
nvarchar
(
10
),Sage
datetime
,Ssex
nvarchar
(
10
))
insert
into
Student
values
(
'
01
'
, N
'
赵雷
'
,
'
1990-01-01
'
, N
'
男
'
)
insert
into
Student
values
(
'
02
'
, N
'
钱电
'
,
'
1990-12-21
'
, N
'
男
'
)
insert
into
Student
values
(
'
03
'
, N
'
孙风
'
,
'
1990-05-20
'
, N
'
男
'
)
insert
into
Student
values
(
'
04
'
, N
'
李云
'
,
'
1990-08-06
'
, N
'
男
'
)
insert
into
Student
values
(
'
05
'
, N
'
周梅
'
,
'
1991-12-01
'
, N
'
女
'
)
insert
into
Student
values
(
'
06
'
, N
'
吴兰
'
,
'
1992-03-01
'
, N
'
女
'
)
insert
into
Student
values
(
'
07
'
, N
'
郑竹
'
,
'
1989-07-01
'
, N
'
女
'
)
insert
into
Student
values
(
'
08
'
, N
'
王菊
'
,
'
1990-01-20
'
, N
'
女
'
)
create
table
Course(C#
varchar
(
10
),Cname
nvarchar
(
10
),T#
varchar
(
10
))
insert
into
Course
values
(
'
01
'
, N
'
语文
'
,
'
02
'
)
insert
into
Course
values
(
'
02
'
, N
'
数学
'
,
'
01
'
)
insert
into
Course
values
(
'
03
'
, N
'
英语
'
,
'
03
'
)
create
table
Teacher(T#
varchar
(
10
),Tname
nvarchar
(
10
))
insert
into
Teacher
values
(
'
01
'
, N
'
张三
'
)
insert
into
Teacher
values
(
'
02
'
, N
'
李四
'
)
insert
into
Teacher
values
(
'
03
'
, N
'
王五
'
)
create
table
SC(S#
varchar
(
10
),C#
varchar
(
10
),score
decimal
(
18
,
1
))
insert
into
SC
values
(
'
01
'
,
'
01
'
,
80
)
insert
into
SC
values
(
'
01
'
,
'
02
'
,
90
)
insert
into
SC
values
(
'
01
'
,
'
03
'
,
99
)
insert
into
SC
values
(
'
02
'
,
'
01
'
,
70
)
insert
into
SC
values
(
'
02
'
,
'
02
'
,
60
)
insert
into
SC
values
(
'
02
'
,
'
03
'
,
80
)
insert
into
SC
values
(
'
03
'
,
'
01
'
,
80
)
insert
into
SC
values
(
'
03
'
,
'
02
'
,
80
)
insert
into
SC
values
(
'
03
'
,
'
03
'
,
80
)
insert
into
SC
values
(
'
04
'
,
'
01
'
,
50
)
insert
into
SC
values
(
'
04
'
,
'
02
'
,
30
)
insert
into
SC
values
(
'
04
'
,
'
03
'
,
20
)
insert
into
SC
values
(
'
05
'
,
'
01
'
,
76
)
insert
into
SC
values
(
'
05
'
,
'
02
'
,
87
)
insert
into
SC
values
(
'
06
'
,
'
01
'
,
31
)
insert
into
SC
values
(
'
06
'
,
'
03
'
,
34
)
insert
into
SC
values
(
'
07
'
,
'
02
'
,
89
)
insert
into
SC
values
(
'
07
'
,
'
03
'
,
98
)
go
--
1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数
--
1.1、查询同时存在"01"课程和"02"课程的情况
select
a.
*
, b.score
[
课程'01'的分数
]
,c.score
[
课程'02'的分数
]
from
Student a , SC b , SC c
where
a.S#
=
b.S#
and
a.S#
=
c.S#
and
b.C#
=
'
01
'
and
c.C#
=
'
02
'
and
b.score
>
c.score
--
1.2、查询同时存在"01"课程和"02"课程的情况和存在"01"课程但可能不存在"02"课程的情况(不存在时显示为null)(以下存在相同内容时不再解释)
select
a.
*
, b.score
[
课程"01"的分数
]
,c.score
[
课程"02"的分数
]
from
Student a
left
join
SC b
on
a.S#
=
b.S#
and
b.C#
=
'
01
'
left
join
SC c
on
a.S#
=
c.S#
and
c.C#
=
'
02
'
where
b.score
>
isnull
(c.score,
0
)
--
2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数
--
2.1、查询同时存在"01"课程和"02"课程的情况
select
a.
*
, b.score
[
课程'01'的分数
]
,c.score
[
课程'02'的分数
]
from
Student a , SC b , SC c
where
a.S#
=
b.S#
and
a.S#
=
c.S#
and
b.C#
=
'
01
'
and
c.C#
=
'
02
'
and
b.score
<
c.score
--
2.2、查询同时存在"01"课程和"02"课程的情况和不存在"01"课程但存在"02"课程的情况
select
a.
*
, b.score
[
课程"01"的分数
]
,c.score
[
课程"02"的分数
]
from
Student a
left
join
SC b
on
a.S#
=
b.S#
and
b.C#
=
'
01
'
left
join
SC c
on
a.S#
=
c.S#
and
c.C#
=
'
02
'
where
isnull
(b.score,
0
)
<
c.score
--
3、查询平均成绩大于等于60分的同学的学生编号和学生姓名和平均成绩
select
a.S# , a.Sname ,
cast
(
avg
(b.score)
as
decimal
(
18
,
2
)) avg_score
from
Student a , sc b
where
a.S#
=
b.S#
group
by
a.S# , a.Sname
having
cast
(
avg
(b.score)
as
decimal
(
18
,
2
))
>=
60
order
by
a.S#
--
4、查询平均成绩小于60分的同学的学生编号和学生姓名和平均成绩
--
4.1、查询在sc表存在成绩的学生信息的SQL语句。
select
a.S# , a.Sname ,
cast
(
avg
(b.score)
as
decimal
(
18
,
2
)) avg_score
from
Student a , sc b
where
a.S#
=
b.S#
group
by
a.S# , a.Sname
having
cast
(
avg
(b.score)
as
decimal
(
18
,
2
))
<
60
order
by
a.S#
--
4.2、查询在sc表中不存在成绩的学生信息的SQL语句。
select
a.S# , a.Sname ,
isnull
(
cast
(
avg
(b.score)
as
decimal
(
18
,
2
)),
0
) avg_score
from
Student a
left
join
sc b
on
a.S#
=
b.S#
group
by
a.S# , a.Sname
having
isnull
(
cast
(
avg
(b.score)
as
decimal
(
18
,
2
)),
0
)
<
60
order
by
a.S#
--
5、查询所有同学的学生编号、学生姓名、选课总数、所有课程的总成绩
--
5.1、查询所有有成绩的SQL。
select
a.S#
[
学生编号
]
, a.Sname
[
学生姓名
]
,
count
(b.C#) 选课总数,
sum
(score)
[
所有课程的总成绩
]
from
Student a , SC b
where
a.S#
=
b.S#
group
by
a.S#,a.Sname
order
by
a.S#
--
5.2、查询所有(包括有成绩和无成绩)的SQL。
select
a.S#
[
学生编号
]
, a.Sname
[
学生姓名
]
,
count
(b.C#) 选课总数,
sum
(score)
[
所有课程的总成绩
]
from
Student a
left
join
SC b
on
a.S#
=
b.S#
group
by
a.S#,a.Sname
order
by
a.S#
--
6、查询"李"姓老师的数量
--
方法1
select
count
(Tname)
[
"李"姓老师的数量
]
from
Teacher
where
Tname
like
N
'
李%
'
--
方法2
select
count
(Tname)
[
"李"姓老师的数量
]
from
Teacher
where
left
(Tname,
1
)
=
N
'
李
'
/*
"李"姓老师的数量 ----------- 1
*/
--
7、查询学过"张三"老师授课的同学的信息
select
distinct
Student.
*
from
Student , SC , Course , Teacher
where
Student.S#
=
SC.S#
and
SC.C#
=
Course.C#
and
Course.T#
=
Teacher.T#
and
Teacher.Tname
=
N
'
张三
'
order
by
Student.S#
--
8、查询没学过"张三"老师授课的同学的信息
select
m.
*
from
Student m
where
S#
not
in
(
select
distinct
SC.S#
from
SC , Course , Teacher
where
SC.C#
=
Course.C#
and
Course.T#
=
Teacher.T#
and
Teacher.Tname
=
N
'
张三
'
)
order
by
m.S#
--
9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息
--
方法1
select
Student.
*
from
Student , SC
where
Student.S#
=
SC.S#
and
SC.C#
=
'
01
'
and
exists
(
Select
1
from
SC SC_2
where
SC_2.S#
=
SC.S#
and
SC_2.C#
=
'
02
'
)
order
by
Student.S#
--
方法2
select
Student.
*
from
Student , SC
where
Student.S#
=
SC.S#
and
SC.C#
=
'
02
'
and
exists
(
Select
1
from
SC SC_2
where
SC_2.S#
=
SC.S#
and
SC_2.C#
=
'
01
'
)
order
by
Student.S#
--
方法3
select
m.
*
from
Student m
where
S#
in
(
select
S#
from
(
select
distinct
S#
from
SC
where
C#
=
'
01
'
union
all
select
distinct
S#
from
SC
where
C#
=
'
02
'
) t
group
by
S#
having
count
(
1
)
=
2
)
order
by
m.S#
--
10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息
--
方法1
select
Student.
*
from
Student , SC
where
Student.S#
=
SC.S#
and
SC.C#
=
'
01
'
and
not
exists
(
Select
1
from
SC SC_2
where
SC_2.S#
=
SC.S#
and
SC_2.C#
=
'
02
'
)
order
by
Student.S#
--
方法2
select
Student.
*
from
Student , SC
where
Student.S#
=
SC.S#
and
SC.C#
=
'
01
'
and
Student.S#
not
in
(
Select
SC_2.S#
from
SC SC_2
where
SC_2.S#
=
SC.S#
and
SC_2.C#
=
'
02
'
)
order
by
Student.S#
--
11、查询没有学全所有课程的同学的信息
--
11.1、
select
Student.
*
from
Student , SC
where
Student.S#
=
SC.S#
group
by
Student.S# , Student.Sname , Student.Sage , Student.Ssex
having
count
(C#)
<
(
select
count
(C#)
from
Course)
--
11.2
select
Student.
*
from
Student
left
join
SC
on
Student.S#
=
SC.S#
group
by
Student.S# , Student.Sname , Student.Sage , Student.Ssex
having
count
(C#)
<
(
select
count
(C#)
from
Course)
--
12、查询至少有一门课与学号为"01"的同学所学相同的同学的信息
select
distinct
Student.
*
from
Student , SC
where
Student.S#
=
SC.S#
and
SC.C#
in
(
select
C#
from
SC
where
S#
=
'
01
'
)
and
Student.S#
<>
'
01
'
--
13、查询和"01"号的同学学习的课程完全相同的其他同学的信息
select
Student.
*
from
Student
where
S#
in
(
select
distinct
SC.S#
from
SC
where
S#
<>
'
01
'
and
SC.C#
in
(
select
distinct
C#
from
SC
where
S#
=
'
01
'
)
group
by
SC.S#
having
count
(
1
)
=
(
select
count
(
1
)
from
SC
where
S#
=
'
01
'
))
--
14、查询没学过"张三"老师讲授的任一门课程的学生姓名
select
student.
*
from
student
where
student.S#
not
in
(
select
distinct
sc.S#
from
sc , course , teacher
where
sc.C#
=
course.C#
and
course.T#
=
teacher.T#
and
teacher.tname
=
N
'
张三
'
)
order
by
student.S#
--
15、查询两门及其以上不及格课程的同学的学号,姓名及其平均成绩
select
student.S# , student.sname ,
cast
(
avg
(score)
as
decimal
(
18
,
2
)) avg_score
from
student , sc
where
student.S#
=
SC.S#
and
student.S#
in
(
select
S#
from
SC
where
score
<
60
group
by
S#
having
count
(
1
)
>=
2
)
group
by
student.S# , student.sname
--
16、检索"01"课程分数小于60,按分数降序排列的学生信息
select
student.
*
, sc.C# , sc.score
from
student , sc
where
student.S#
=
SC.S#
and
sc.score
<
60
and
sc.C#
=
'
01
'
order
by
sc.score
desc
--
17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩
--
17.1 SQL 2000 静态
select
a.S# 学生编号 , a.Sname 学生姓名 ,
max
(
case
c.Cname
when
N
'
语文
'
then
b.score
else
null
end
)
[
语文
]
,
max
(
case
c.Cname
when
N
'
数学
'
then
b.score
else
null
end
)
[
数学
]
,
max
(
case
c.Cname
when
N
'
英语
'
then
b.score
else
null
end
)
[
英语
]
,
cast
(
avg
(b.score)
as
decimal
(
18
,
2
)) 平均分
from
Student a
left
join
SC b
on
a.S#
=
b.S#
left
join
Course c
on
b.C#
=
c.C#
group
by
a.S# , a.Sname
order
by
平均分
desc
--
17.2 SQL 2000 动态
declare
@sql
nvarchar
(
4000
)
set
@sql
=
'
select a.S#
'
+
N
'
学生编号
'
+
'
, a.Sname
'
+
N
'
学生姓名
'
select
@sql
=
@sql
+
'
,max(case c.Cname when N
'''
+
Cname
+
'''
then b.score else null end) [
'
+
Cname
+
'
]
'
from
(
select
distinct
Cname
from
Course)
as
t
set
@sql
=
@sql
+
'
, cast(avg(b.score) as decimal(18,2))
'
+
N
'
平均分
'
+
'
from Student a left join SC b on a.S# = b.S# left join Course c on b.C# = c.C# group by a.S# , a.Sname order by
'
+
N
'
平均分
'
+
'
desc
'
exec
(
@sql
)
--
17.3 有关sql 2005的动静态写法参见我的文章《普通行列转换(version 2.0)》或《普通行列转换(version 3.0)》。
SQL code
--
18、查询各科成绩最高分、最低分和平均分:以如下形式显示:课程ID,课程name,最高分,最低分,平均分,及格率,中等率,优良率,优秀率
--
及格为>=60,中等为:70-80,优良为:80-90,优秀为:>=90
--
方法1
select
m.C#
[
课程编号
]
, m.Cname
[
课程名称
]
,
max
(n.score)
[
最高分
]
,
min
(n.score)
[
最低分
]
,
cast
(
avg
(n.score)
as
decimal
(
18
,
2
))
[
平均分
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
60
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
及格率(%)
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
70
and
score
<
80
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
中等率(%)
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
80
and
score
<
90
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
优良率(%)
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
90
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
优秀率(%)
]
from
Course m , SC n
where
m.C#
=
n.C#
group
by
m.C# , m.Cname
order
by
m.C#
--
方法2
select
m.C#
[
课程编号
]
, m.Cname
[
课程名称
]
, (
select
max
(score)
from
SC
where
C#
=
m.C#)
[
最高分
]
, (
select
min
(score)
from
SC
where
C#
=
m.C#)
[
最低分
]
, (
select
cast
(
avg
(score)
as
decimal
(
18
,
2
))
from
SC
where
C#
=
m.C#)
[
平均分
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
60
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
及格率(%)
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
70
and
score
<
80
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
中等率(%)
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
80
and
score
<
90
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
优良率(%)
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
90
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
优秀率(%)
]
from
Course m
order
by
m.C#
--
19、按各科成绩进行排序,并显示排名
--
19.1 sql 2000用子查询完成
--
Score重复时保留名次空缺
select
t.
*
, px
=
(
select
count
(
1
)
from
SC
where
C#
=
t.C#
and
score
>
t.score)
+
1
from
sc t
order
by
t.c# , px
--
Score重复时合并名次
select
t.
*
, px
=
(
select
count
(
distinct
score)
from
SC
where
C#
=
t.C#
and
score
>=
t.score)
from
sc t
order
by
t.c# , px
--
19.2 sql 2005用rank,DENSE_RANK完成
--
Score重复时保留名次空缺(rank完成)
select
t.
*
, px
=
rank()
over
(partition
by
c#
order
by
score
desc
)
from
sc t
order
by
t.C# , px
--
Score重复时合并名次(DENSE_RANK完成)
select
t.
*
, px
=
DENSE_RANK()
over
(partition
by
c#
order
by
score
desc
)
from
sc t
order
by
t.C# , px
--
20、查询学生的总成绩并进行排名
--
20.1 查询学生的总成绩
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
sum
(score),
0
)
[
总成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname
order
by
[
总成绩
]
desc
--
20.2 查询学生的总成绩并进行排名,sql 2000用子查询完成,分总分重复时保留名次空缺和不保留名次空缺两种。
select
t1.
*
, px
=
(
select
count
(
1
)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
sum
(score),
0
)
[
总成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t2
where
总成绩
>
t1.总成绩)
+
1
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
sum
(score),
0
)
[
总成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t1
order
by
px
select
t1.
*
, px
=
(
select
count
(
distinct
总成绩)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
sum
(score),
0
)
[
总成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t2
where
总成绩
>=
t1.总成绩)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
sum
(score),
0
)
[
总成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t1
order
by
px
--
20.3 查询学生的总成绩并进行排名,sql 2005用rank,DENSE_RANK完成,分总分重复时保留名次空缺和不保留名次空缺两种。
select
t.
*
, px
=
rank()
over
(
order
by
[
总成绩
]
desc
)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
sum
(score),
0
)
[
总成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t
order
by
px
select
t.
*
, px
=
DENSE_RANK()
over
(
order
by
[
总成绩
]
desc
)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
sum
(score),
0
)
[
总成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t
order
by
px
--
21、查询不同老师所教不同课程平均分从高到低显示
select
m.T# , m.Tname ,
cast
(
avg
(o.score)
as
decimal
(
18
,
2
)) avg_score
from
Teacher m , Course n , SC o
where
m.T#
=
n.T#
and
n.C#
=
o.C#
group
by
m.T# , m.Tname
order
by
avg_score
desc
--
22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩
--
22.1 sql 2000用子查询完成
--
Score重复时保留名次空缺
select
*
from
(
select
t.
*
, px
=
(
select
count
(
1
)
from
SC
where
C#
=
t.C#
and
score
>
t.score)
+
1
from
sc t) m
where
px
between
2
and
3
order
by
m.c# , m.px
--
Score重复时合并名次
select
*
from
(
select
t.
*
, px
=
(
select
count
(
distinct
score)
from
SC
where
C#
=
t.C#
and
score
>=
t.score)
from
sc t) m
where
px
between
2
and
3
order
by
m.c# , m.px
--
22.2 sql 2005用rank,DENSE_RANK完成
--
Score重复时保留名次空缺(rank完成)
select
*
from
(
select
t.
*
, px
=
rank()
over
(partition
by
c#
order
by
score
desc
)
from
sc t) m
where
px
between
2
and
3
order
by
m.C# , m.px
--
Score重复时合并名次(DENSE_RANK完成)
select
*
from
(
select
t.
*
, px
=
DENSE_RANK()
over
(partition
by
c#
order
by
score
desc
)
from
sc t) m
where
px
between
2
and
3
order
by
m.C# , m.px
--
23、统计各科成绩各分数段人数:课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]及所占百分比
--
23.1 统计各科成绩各分数段人数:课程编号,课程名称,[100-85],[85-70],[70-60],[0-60]
--
横向显示
select
Course.C#
[
课程编号
]
, Cname
as
[
课程名称
]
,
sum
(
case
when
score
>=
85
then
1
else
0
end
)
[
85-100
]
,
sum
(
case
when
score
>=
70
and
score
<
85
then
1
else
0
end
)
[
70-85
]
,
sum
(
case
when
score
>=
60
and
score
<
70
then
1
else
0
end
)
[
60-70
]
,
sum
(
case
when
score
<
60
then
1
else
0
end
)
[
0-60
]
from
sc , Course
where
SC.C#
=
Course.C#
group
by
Course.C# , Course.Cname
order
by
Course.C#
--
纵向显示1(显示存在的分数段)
select
m.C#
[
课程编号
]
, m.Cname
[
课程名称
]
, 分数段
=
(
case
when
n.score
>=
85
then
'
85-100
'
when
n.score
>=
70
and
n.score
<
85
then
'
70-85
'
when
n.score
>=
60
and
n.score
<
70
then
'
60-70
'
else
'
0-60
'
end
) ,
count
(
1
) 数量
from
Course m , sc n
where
m.C#
=
n.C#
group
by
m.C# , m.Cname , (
case
when
n.score
>=
85
then
'
85-100
'
when
n.score
>=
70
and
n.score
<
85
then
'
70-85
'
when
n.score
>=
60
and
n.score
<
70
then
'
60-70
'
else
'
0-60
'
end
)
order
by
m.C# , m.Cname , 分数段
--
纵向显示2(显示存在的分数段,不存在的分数段用0显示)
select
m.C#
[
课程编号
]
, m.Cname
[
课程名称
]
, 分数段
=
(
case
when
n.score
>=
85
then
'
85-100
'
when
n.score
>=
70
and
n.score
<
85
then
'
70-85
'
when
n.score
>=
60
and
n.score
<
70
then
'
60-70
'
else
'
0-60
'
end
) ,
count
(
1
) 数量
from
Course m , sc n
where
m.C#
=
n.C#
group
by
all
m.C# , m.Cname , (
case
when
n.score
>=
85
then
'
85-100
'
when
n.score
>=
70
and
n.score
<
85
then
'
70-85
'
when
n.score
>=
60
and
n.score
<
70
then
'
60-70
'
else
'
0-60
'
end
)
order
by
m.C# , m.Cname , 分数段
--
23.2 统计各科成绩各分数段人数:课程编号,课程名称,[100-85],[85-70],[70-60],[<60]及所占百分比
--
横向显示
select
m.C# 课程编号, m.Cname 课程名称, (
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
<
60
)
[
0-60
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
<
60
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
百分比(%)
]
, (
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
60
and
score
<
70
)
[
60-70
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
60
and
score
<
70
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
百分比(%)
]
, (
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
70
and
score
<
85
)
[
70-85
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
70
and
score
<
85
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
百分比(%)
]
, (
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
85
)
[
85-100
]
,
cast
((
select
count
(
1
)
from
SC
where
C#
=
m.C#
and
score
>=
85
)
*
100.0
/
(
select
count
(
1
)
from
SC
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
百分比(%)
]
from
Course m
order
by
m.C#
--
纵向显示1(显示存在的分数段)
select
m.C#
[
课程编号
]
, m.Cname
[
课程名称
]
, 分数段
=
(
case
when
n.score
>=
85
then
'
85-100
'
when
n.score
>=
70
and
n.score
<
85
then
'
70-85
'
when
n.score
>=
60
and
n.score
<
70
then
'
60-70
'
else
'
0-60
'
end
) ,
count
(
1
) 数量 ,
cast
(
count
(
1
)
*
100.0
/
(
select
count
(
1
)
from
sc
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
百分比(%)
]
from
Course m , sc n
where
m.C#
=
n.C#
group
by
m.C# , m.Cname , (
case
when
n.score
>=
85
then
'
85-100
'
when
n.score
>=
70
and
n.score
<
85
then
'
70-85
'
when
n.score
>=
60
and
n.score
<
70
then
'
60-70
'
else
'
0-60
'
end
)
order
by
m.C# , m.Cname , 分数段
--
纵向显示2(显示存在的分数段,不存在的分数段用0显示)
select
m.C#
[
课程编号
]
, m.Cname
[
课程名称
]
, 分数段
=
(
case
when
n.score
>=
85
then
'
85-100
'
when
n.score
>=
70
and
n.score
<
85
then
'
70-85
'
when
n.score
>=
60
and
n.score
<
70
then
'
60-70
'
else
'
0-60
'
end
) ,
count
(
1
) 数量 ,
cast
(
count
(
1
)
*
100.0
/
(
select
count
(
1
)
from
sc
where
C#
=
m.C#)
as
decimal
(
18
,
2
))
[
百分比(%)
]
from
Course m , sc n
where
m.C#
=
n.C#
group
by
all
m.C# , m.Cname , (
case
when
n.score
>=
85
then
'
85-100
'
when
n.score
>=
70
and
n.score
<
85
then
'
70-85
'
when
n.score
>=
60
and
n.score
<
70
then
'
60-70
'
else
'
0-60
'
end
)
order
by
m.C# , m.Cname , 分数段
SQL code
--
24、查询学生平均成绩及其名次
--
24.1 查询学生的平均成绩并进行排名,sql 2000用子查询完成,分平均成绩重复时保留名次空缺和不保留名次空缺两种。
select
t1.
*
, px
=
(
select
count
(
1
)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
cast
(
avg
(score)
as
decimal
(
18
,
2
)),
0
)
[
平均成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t2
where
平均成绩
>
t1.平均成绩)
+
1
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
cast
(
avg
(score)
as
decimal
(
18
,
2
)),
0
)
[
平均成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t1
order
by
px
select
t1.
*
, px
=
(
select
count
(
distinct
平均成绩)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
cast
(
avg
(score)
as
decimal
(
18
,
2
)),
0
)
[
平均成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t2
where
平均成绩
>=
t1.平均成绩)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
cast
(
avg
(score)
as
decimal
(
18
,
2
)),
0
)
[
平均成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t1
order
by
px
--
24.2 查询学生的平均成绩并进行排名,sql 2005用rank,DENSE_RANK完成,分平均成绩重复时保留名次空缺和不保留名次空缺两种。
select
t.
*
, px
=
rank()
over
(
order
by
[
平均成绩
]
desc
)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
cast
(
avg
(score)
as
decimal
(
18
,
2
)),
0
)
[
平均成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t
order
by
px
select
t.
*
, px
=
DENSE_RANK()
over
(
order
by
[
平均成绩
]
desc
)
from
(
select
m.S#
[
学生编号
]
, m.Sname
[
学生姓名
]
,
isnull
(
cast
(
avg
(score)
as
decimal
(
18
,
2
)),
0
)
[
平均成绩
]
from
Student m
left
join
SC n
on
m.S#
=
n.S#
group
by
m.S# , m.Sname ) t
order
by
px
--
25、查询各科成绩前三名的记录
--
25.1 分数重复时保留名次空缺
select
m.
*
, n.C# , n.score
from
Student m, SC n
where
m.S#
=
n.S#
and
n.score
in
(
select
top
3
score
from
sc
where
C#
=
n.C#
order
by
score
desc
)
order
by
n.C# , n.score
desc
--
25.2 分数重复时不保留名次空缺,合并名次
--
sql 2000用子查询实现
select
*
from
(
select
t.
*
, px
=
(
select
count
(
distinct
score)
from
SC
where
C#
=
t.C#
and
score
>=
t.score)
from
sc t) m
where
px
between
1
and
3
order
by
m.c# , m.px
--
sql 2005用DENSE_RANK实现
select
*
from
(
select
t.
*
, px
=
DENSE_RANK()
over
(partition
by
c#
order
by
score
desc
)
from
sc t) m
where
px
between
1
and
3
order
by
m.C# , m.px
--
26、查询每门课程被选修的学生数
select
c# ,
count
(S#)
[
学生数
]
from
sc
group
by
C#
--
27、查询出只有两门课程的全部学生的学号和姓名
select
Student.S# , Student.Sname
from
Student , SC
where
Student.S#
=
SC.S#
group
by
Student.S# , Student.Sname
having
count
(SC.C#)
=
2
order
by
Student.S#
--
28、查询男生、女生人数
select
count
(Ssex)
as
男生人数
from
Student
where
Ssex
=
N
'
男
'
select
count
(Ssex)
as
女生人数
from
Student
where
Ssex
=
N
'
女
'
select
sum
(
case
when
Ssex
=
N
'
男
'
then
1
else
0
end
)
[
男生人数
]
,
sum
(
case
when
Ssex
=
N
'
女
'
then
1
else
0
end
)
[
女生人数
]
from
student
select
case
when
Ssex
=
N
'
男
'
then
N
'
男生人数
'
else
N
'
女生人数
'
end
[
男女情况
]
,
count
(
1
)
[
人数
]
from
student
group
by
case
when
Ssex
=
N
'
男
'
then
N
'
男生人数
'
else
N
'
女生人数
'
end
--
29、查询名字中含有"风"字的学生信息
select
*
from
student
where
sname
like
N
'
%风%
'
select
*
from
student
where
charindex
(N
'
风
'
, sname)
>
0
--
30、查询同名同性学生名单,并统计同名人数
select
Sname
[
学生姓名
]
,
count
(
*
)
[
人数
]
from
Student
group
by
Sname
having
count
(
*
)
>
1
--
31、查询1990年出生的学生名单(注:Student表中Sage列的类型是datetime)
select
*
from
Student
where
year
(sage)
=
1990
select
*
from
Student
where
datediff
(yy,sage,
'
1990-01-01
'
)
=
0
select
*
from
Student
where
datepart
(yy,sage)
=
1990
select
*
from
Student
where
convert
(
varchar
(
4
),sage,
120
)
=
'
1990
'
--
32、查询每门课程的平均成绩,结果按平均成绩降序排列,平均成绩相同时,按课程编号升序排列
select
m.C# , m.Cname ,
cast
(
avg
(n.score)
as
decimal
(
18
,
2
)) avg_score
from
Course m, SC n
where
m.C#
=
n.C#
group
by
m.C# , m.Cname
order
by
avg_score
desc
, m.C#
asc
--
33、查询平均成绩大于等于85的所有学生的学号、姓名和平均成绩
select
a.S# , a.Sname ,
cast
(
avg
(b.score)
as
decimal
(
18
,
2
)) avg_score
from
Student a , sc b
where
a.S#
=
b.S#
group
by
a.S# , a.Sname
having
cast
(
avg
(b.score)
as
decimal
(
18
,
2
))
>=
85
order
by
a.S#
--
34、查询课程名称为"数学",且分数低于60的学生姓名和分数
select
sname , score
from
Student , SC , Course
where
SC.S#
=
Student.S#
and
SC.C#
=
Course.C#
and
Course.Cname
=
N
'
数学
'
and
score
<
60
--
35、查询所有学生的课程及分数情况;
select
Student.
*
, Course.Cname , SC.C# , SC.score
from
Student, SC , Course
where
Student.S#
=
SC.S#
and
SC.C#
=
Course.C#
order
by
Student.S# , SC.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
Student.
*
, Course.Cname , SC.C# , SC.score
from
Student, SC , Course
where
Student.S#
=
SC.S#
and
SC.C#
=
Course.C#
and
SC.score
>=
70
order
by
Student.S# , SC.C#
--
37、查询不及格的课程
select
Student.
*
, Course.Cname , SC.C# , SC.score
from
Student, SC , Course
where
Student.S#
=
SC.S#
and
SC.C#
=
Course.C#
and
SC.score
<
60
order
by
Student.S# , SC.C#
--
38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名;
select
Student.
*
, Course.Cname , SC.C# , SC.score
from
Student, SC , Course
where
Student.S#
=
SC.S#
and
SC.C#
=
Course.C#
and
SC.C#
=
'
01
'
and
SC.score
>=
80
order
by
Student.S# , SC.C#
--
39、求每门课程的学生人数
select
Course.C# , Course.Cname ,
count
(
*
)
[
学生人数
]
from
Course , SC
where
Course.C#
=
SC.C#
group
by
Course.C# , Course.Cname
order
by
Course.C# , Course.Cname
--
40、查询选修"张三"老师所授课程的学生中,成绩最高的学生信息及其成绩
--
40.1 当最高分只有一个时
select
top
1
Student.
*
, Course.Cname , SC.C# , SC.score
from
Student, SC , Course , Teacher
where
Student.S#
=
SC.S#
and
SC.C#
=
Course.C#
and
Course.T#
=
Teacher.T#
and
Teacher.Tname
=
N
'
张三
'
order
by
SC.score
desc
--
40.2 当最高分出现多个时
select
Student.
*
, Course.Cname , SC.C# , SC.score
from
Student, SC , Course , Teacher
where
Student.S#
=
SC.S#
and
SC.C#
=
Course.C#
and
Course.T#
=
Teacher.T#
and
Teacher.Tname
=
N
'
张三
'
and
SC.score
=
(
select
max
(SC.score)
from
SC , Course , Teacher
where
SC.C#
=
Course.C#
and
Course.T#
=
Teacher.T#
and
Teacher.Tname
=
N
'
张三
'
)
--
41、查询不同课程成绩相同的学生的学生编号、课程编号、学生成绩
--
方法1
select
m.
*
from
SC m ,(
select
C# , score
from
SC
group
by
C# , score
having
count
(
1
)
>
1
) n
where
m.C#
=
n.C#
and
m.score
=
n.score
order
by
m.C# , m.score , m.S#
--
方法2
select
m.
*
from
SC m
where
exists
(
select
1
from
(
select
C# , score
from
SC
group
by
C# , score
having
count
(
1
)
>
1
) n
where
m.C#
=
n.C#
and
m.score
=
n.score)
order
by
m.C# , m.score , m.S#
--
42、查询每门功成绩最好的前两名
select
t.
*
from
sc t
where
score
in
(
select
top
2
score
from
sc
where
C#
=
T.C#
order
by
score
desc
)
order
by
t.C# , t.score
desc
--
43、统计每门课程的学生选修人数(超过5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,若人数相同,按课程号升序排列
select
Course.C# , Course.Cname ,
count
(
*
)
[
学生人数
]
from
Course , SC
where
Course.C#
=
SC.C#
group
by
Course.C# , Course.Cname
having
count
(
*
)
>=
5
order
by
[
学生人数
]
desc
, Course.C#
--
44、检索至少选修两门课程的学生学号
select
student.S# , student.Sname
from
student , SC
where
student.S#
=
SC.S#
group
by
student.S# , student.Sname
having
count
(
1
)
>=
2
order
by
student.S#
--
45、查询选修了全部课程的学生信息
--
方法1 根据数量来完成
select
student.
*
from
student
where
S#
in
(
select
S#
from
sc
group
by
S#
having
count
(
1
)
=
(
select
count
(
1
)
from
course))
--
方法2 使用双重否定来完成
select
t.
*
from
student t
where
t.S#
not
in
(
select
distinct
m.S#
from
(
select
S# , C#
from
student , course ) m
where
not
exists
(
select
1
from
sc n
where
n.S#
=
m.S#
and
n.C#
=
m.C#) )
--
方法3 使用双重否定来完成
select
t.
*
from
student t
where
not
exists
(
select
1
from
(
select
distinct
m.S#
from
(
select
S# , C#
from
student , course ) m
where
not
exists
(
select
1
from
sc n
where
n.S#
=
m.S#
and
n.C#
=
m.C#) ) k
where
k.S#
=
t.S# )
--
46、查询各学生的年龄
--
46.1 只按照年份来算
select
*
,
datediff
(yy , sage ,
getdate
())
[
年龄
]
from
student
--
46.2 按照出生日期来算,当前月日 < 出生年月的月日则,年龄减一
select
*
,
case
when
right
(
convert
(
varchar
(
10
),
getdate
(),
120
),
5
)
<
right
(
convert
(
varchar
(
10
),sage,
120
),
5
)
then
datediff
(yy , sage ,
getdate
())
-
1
else
datediff
(yy , sage ,
getdate
())
end
[
年龄
]
from
student
--
47、查询本周过生日的学生
select
*
from
student
where
datediff
(week,
datename
(yy,
getdate
())
+
right
(
convert
(
varchar
(
10
),sage,
120
),
6
),
getdate
())
=
0
--
48、查询下周过生日的学生
select
*
from
student
where
datediff
(week,
datename
(yy,
getdate
())
+
right
(
convert
(
varchar
(
10
),sage,
120
),
6
),
getdate
())
=
-
1
--
49、查询本月过生日的学生
select
*
from
student
where
datediff
(mm,
datename
(yy,
getdate
())
+
right
(
convert
(
varchar
(
10
),sage,
120
),
6
),
getdate
())
=
0
--
50、查询下月过生日的学生
select
*
from
student
where
datediff
(mm,
datename
(yy,
getdate
())
+
right
(
convert
(
varchar
(
10
),sage,
120
),
6
),
getdate
())
=
-
1
drop
table
Student,Course,Teacher,SC