問題及描述:
--1.學生表
Student(S#,Sname,Sage,Ssex)
--S# 學生編號,Sname 學生姓名,Sage 出生年月,Ssex 學生性別
--2.課程表
Course(C#,Cname,T#)
--C# --課程編號,Cname 課程名稱,T# 教師編號
--3.教師表
Teacher(T#,Tname)
--T# 教師編號,Tname 教師姓名
--4.成績表
SC(S#,C#,score)
--S# 學生編號,C# 課程編號,score 分數
*/
--創建測試數據
create
table
Student(S#
varchar
(10),Sname nvarchar(10),Sage datetime,Ssex nvarchar(10))
insert
into
Student
values
(
'01'
, N
'趙雷'
,
'1990-01-01'
, N
'男'
)
insert
into
Student
values
(
'02'
, N
'錢電'
,
'1990-12-21'
, N
'男'
)
insert
into
Student
values
(
'03'
, N
'孫風'
,
'1990-05-20'
, N
'男'
)
insert
into
Student
values
(
'04'
, N
'李雲'
,
'1990-08-06'
, N
'男'
)
insert
into
Student
values
(
'05'
, N
'周梅'
,
'1991-12-01'
, N
'女'
)
insert
into
Student
values
(
'06'
, N
'吳蘭'
,
'1992-03-01'
, N
'女'
)
insert
into
Student
values
(
'07'
, N
'鄭竹'
,
'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
'語文'
,
'02'
)
insert
into
Course
values
(
'02'
, N
'數學'
,
'01'
)
insert
into
Course
values
(
'03'
, N
'英語'
,
'03'
)
create
table
Teacher(T#
varchar
(10),Tname nvarchar(10))
insert
into
Teacher
values
(
'01'
, N
'張三'
)
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、查詢"01"課程比"02"課程成績高的學生的信息及課程分數
--1.1、查詢同時存在"01"課程和"02"課程的情況
select
a.* , b.score [課程
'01'
的分數],c.score [課程
'02'
的分數]
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、查詢同時存在"01"課程和"02"課程的情況和存在"01"課程但可能不存在"02"課程的情況(不存在時顯示爲null)(以下存在相同內容時不再解釋)
select
a.* , b.score [課程
"01"
的分數],c.score [課程
"02"
的分數]
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、查詢"01"課程比"02"課程成績低的學生的信息及課程分數
--2.1、查詢同時存在"01"課程和"02"課程的情況
select
a.* , b.score [課程
'01'
的分數],c.score [課程
'02'
的分數]
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、查詢同時存在"01"課程和"02"課程的情況和不存在"01"課程但存在"02"課程的情況
select
a.* , b.score [課程
"01"
的分數],c.score [課程
"02"
的分數]
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、查詢平均成績大於等於60分的同學的學生編號和學生姓名和平均成績
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、查詢平均成績小於60分的同學的學生編號和學生姓名和平均成績
--4.1、查詢在sc表存在成績的學生信息的SQL語句。
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、查詢在sc表中不存在成績的學生信息的SQL語句。
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、查詢所有同學的學生編號、學生姓名、選課總數、所有課程的總成績
--5.1、查詢所有有成績的SQL。
select
a.S# [學生編號], a.Sname [學生姓名],
count
(b.C#) 選課總數,
sum
(score) [所有課程的總成績]
from
Student a , SC b
where
a.S# = b.S#
group
by
a.S#,a.Sname
order
by
a.S#
--5.2、查詢所有(包括有成績和無成績)的SQL。
select
a.S# [學生編號], a.Sname [學生姓名],
count
(b.C#) 選課總數,
sum
(score) [所有課程的總成績]
from
Student a
left
join
SC b
on
a.S# = b.S#
group
by
a.S#,a.Sname
order
by
a.S#
--6、查詢"李"姓老師的數量
--方法1
select
count
(Tname) [
"李"
姓老師的數量]
from
Teacher
where
Tname
like
N
'李%'
--方法2
select
count
(Tname) [
"李"
姓老師的數量]
from
Teacher
where
left
(Tname,1) = N
'李'
/*
"李"
姓老師的數量
-----------
1
*/
--7、查詢學過"張三"老師授課的同學的信息
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
'張三'
order
by
Student.S#
--8、查詢沒學過"張三"老師授課的同學的信息
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
'張三'
)
order
by
m.S#
--9、查詢學過編號爲"01"並且也學過編號爲"02"的課程的同學的信息
--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、查詢學過編號爲"01"但是沒有學過編號爲"02"的課程的同學的信息
--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、查詢沒有學全所有課程的同學的信息
--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、查詢至少有一門課與學號爲"01"的同學所學相同的同學的信息
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、查詢和"01"號的同學學習的課程完全相同的其他同學的信息
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、查詢沒學過"張三"老師講授的任一門課程的學生姓名
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
'張三'
)
order
by
student.S#
--15、查詢兩門及其以上不及格課程的同學的學號,姓名及其平均成績
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、檢索"01"課程分數小於60,按分數降序排列的學生信息
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、按平均成績從高到低顯示所有學生的所有課程的成績以及平均成績
--17.1 SQL 2000 靜態
select
a.S# 學生編號 , a.Sname 學生姓名 ,
max
(
case
c.Cname
when
N
'語文'
then
b.score
else
null
end
) [語文],
max
(
case
c.Cname
when
N
'數學'
then
b.score
else
null
end
) [數學],
max
(
case
c.Cname
when
N
'英語'
then
b.score
else
null
end
) [英語],
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 動態
declare
@sql nvarchar(4000)
set
@sql =
'select a.S# '
+ N
'學生編號'
+
' , a.Sname '
+ N
'學生姓名'
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 有關sql 2005的動靜態寫法參見我的文章《普通行列轉換(version 2.0)》或《普通行列轉換(version 3.0)》。
--18、查詢各科成績最高分、最低分和平均分:以如下形式顯示:課程ID,課程name,最高分,最低分,平均分,及格率,中等率,優良率,優秀率
--及格爲>=60,中等爲:70-80,優良爲:80-90,優秀爲:>=90
--方法1
select
m.C# [課程編號], m.Cname [課程名稱],
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)) [優良率(%)],
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)) [優秀率(%)]
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# [課程編號], m.Cname [課程名稱],
(
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)) [優良率(%)],
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)) [優秀率(%)]
from
Course m
order
by
m.C#
--19、按各科成績進行排序,並顯示排名
--19.1 sql 2000用子查詢完成
--Score重複時保留名次空缺
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重複時合併名次
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重複時保留名次空缺(rank完成)
select
t.* , px = rank() over(partition
by
c#
order
by
score
desc
)
from
sc t
order
by
t.C# , px
--Score重複時合併名次(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、查詢學生的總成績並進行排名
--20.1 查詢學生的總成績
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
sum
(score),0) [總成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
order
by
[總成績]
desc
--20.2 查詢學生的總成績並進行排名,sql 2000用子查詢完成,分總分重複時保留名次空缺和不保留名次空缺兩種。
select
t1.* , px = (
select
count
(1)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
sum
(score),0) [總成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
) t2
where
總成績 > t1.總成績) + 1
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
sum
(score),0) [總成績]
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
總成績)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
sum
(score),0) [總成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
) t2
where
總成績 >= t1.總成績)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
sum
(score),0) [總成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
) t1
order
by
px
--20.3 查詢學生的總成績並進行排名,sql 2005用rank,DENSE_RANK完成,分總分重複時保留名次空缺和不保留名次空缺兩種。
select
t.* , px = rank() over(
order
by
[總成績]
desc
)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
sum
(score),0) [總成績]
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
[總成績]
desc
)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
sum
(score),0) [總成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
) t
order
by
px
--21、查詢不同老師所教不同課程平均分從高到低顯示
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、查詢所有課程的成績第2名到第3名的學生信息及該課程成績
--22.1 sql 2000用子查詢完成
--Score重複時保留名次空缺
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重複時合併名次
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重複時保留名次空缺(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重複時合併名次(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、統計各科成績各分數段人數:課程編號,課程名稱,[100-85],[85-70],[70-60],[0-60]及所佔百分比
--23.1 統計各科成績各分數段人數:課程編號,課程名稱,[100-85],[85-70],[70-60],[0-60]
--橫向顯示
select
Course.C# [課程編號] , Cname
as
[課程名稱] ,
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#
--縱向顯示1(顯示存在的分數段)
select
m.C# [課程編號] , m.Cname [課程名稱] , 分數段 = (
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) 數量
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 , 分數段
--縱向顯示2(顯示存在的分數段,不存在的分數段用0顯示)
select
m.C# [課程編號] , m.Cname [課程名稱] , 分數段 = (
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) 數量
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 , 分數段
--23.2 統計各科成績各分數段人數:課程編號,課程名稱,[100-85],[85-70],[70-60],[<60]及所佔百分比
--橫向顯示
select
m.C# 課程編號, m.Cname 課程名稱,
(
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#
--縱向顯示1(顯示存在的分數段)
select
m.C# [課程編號] , m.Cname [課程名稱] , 分數段 = (
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) 數量 ,
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 , 分數段
--縱向顯示2(顯示存在的分數段,不存在的分數段用0顯示)
select
m.C# [課程編號] , m.Cname [課程名稱] , 分數段 = (
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) 數量 ,
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 , 分數段
--24、查詢學生平均成績及其名次
--24.1 查詢學生的平均成績並進行排名,sql 2000用子查詢完成,分平均成績重複時保留名次空缺和不保留名次空缺兩種。
select
t1.* , px = (
select
count
(1)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
cast
(
avg
(score)
as
decimal
(18,2)),0) [平均成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
) t2
where
平均成績 > t1.平均成績) + 1
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
cast
(
avg
(score)
as
decimal
(18,2)),0) [平均成績]
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
平均成績)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
cast
(
avg
(score)
as
decimal
(18,2)),0) [平均成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
) t2
where
平均成績 >= t1.平均成績)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
cast
(
avg
(score)
as
decimal
(18,2)),0) [平均成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
) t1
order
by
px
--24.2 查詢學生的平均成績並進行排名,sql 2005用rank,DENSE_RANK完成,分平均成績重複時保留名次空缺和不保留名次空缺兩種。
select
t.* , px = rank() over(
order
by
[平均成績]
desc
)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
cast
(
avg
(score)
as
decimal
(18,2)),0) [平均成績]
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
[平均成績]
desc
)
from
(
select
m.S# [學生編號] ,
m.Sname [學生姓名] ,
isnull
(
cast
(
avg
(score)
as
decimal
(18,2)),0) [平均成績]
from
Student m
left
join
SC n
on
m.S# = n.S#
group
by
m.S# , m.Sname
) t
order
by
px
--25、查詢各科成績前三名的記錄
--25.1 分數重複時保留名次空缺
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 分數重複時不保留名次空缺,合併名次
--sql 2000用子查詢實現
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實現
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、查詢每門課程被選修的學生數
select
c# ,
count
(S#)[學生數]
from
sc
group
by
C#
--27、查詢出只有兩門課程的全部學生的學號和姓名
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、查詢男生、女生人數
select
count
(Ssex)
as
男生人數
from
Student
where
Ssex = N
'男'
select
count
(Ssex)
as
女生人數
from
Student
where
Ssex = N
'女'
select
sum
(
case
when
Ssex = N
'男'
then
1
else
0
end
) [男生人數],
sum
(
case
when
Ssex = N
'女'
then
1
else
0
end
) [女生人數]
from
student
select
case
when
Ssex = N
'男'
then
N
'男生人數'
else
N
'女生人數'
end
[男女情況] ,
count
(1) [人數]
from
student
group
by
case
when
Ssex = N
'男'
then
N
'男生人數'
else
N
'女生人數'
end
--29、查詢名字中含有"風"字的學生信息
select
*
from
student
where
sname
like
N
'%風%'
select
*
from
student
where
charindex(N
'風'
, sname) > 0
--30、查詢同名同性學生名單,並統計同名人數
select
Sname [學生姓名],
count
(*) [人數]
from
Student
group
by
Sname
having
count
(*) > 1
--31、查詢1990年出生的學生名單(注:Student表中Sage列的類型是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、查詢每門課程的平均成績,結果按平均成績降序排列,平均成績相同時,按課程編號升序排列
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、查詢平均成績大於等於85的所有學生的學號、姓名和平均成績
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、查詢課程名稱爲"數學",且分數低於60的學生姓名和分數
select
sname , score
from
Student , SC , Course
where
SC.S# = Student.S#
and
SC.C# = Course.C#
and
Course.Cname = N
'數學'
and
score < 60
--35、查詢所有學生的課程及分數情況;
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、查詢任何一門課程成績在70分以上的姓名、課程名稱和分數;
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、查詢不及格的課程
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、查詢課程編號爲01且課程成績在80分以上的學生的學號和姓名;
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、求每門課程的學生人數
select
Course.C# , Course.Cname ,
count
(*) [學生人數]
from
Course , SC
where
Course.C# = SC.C#
group
by
Course.C# , Course.Cname
order
by
Course.C# , Course.Cname
--40、查詢選修"張三"老師所授課程的學生中,成績最高的學生信息及其成績
--40.1 當最高分只有一個時
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
'張三'
order
by
SC.score
desc
--40.2 當最高分出現多個時
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
'張三'
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
'張三'
)
--41、查詢不同課程成績相同的學生的學生編號、課程編號、學生成績
--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、查詢每門功成績最好的前兩名
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、統計每門課程的學生選修人數(超過5人的課程才統計)。要求輸出課程號和選修人數,查詢結果按人數降序排列,若人數相同,按課程號升序排列
select
Course.C# , Course.Cname ,
count
(*) [學生人數]
from
Course , SC
where
Course.C# = SC.C#
group
by
Course.C# , Course.Cname
having
count
(*) >= 5
order
by
[學生人數]
desc
, Course.C#
--44、檢索至少選修兩門課程的學生學號
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、查詢選修了全部課程的學生信息
--方法1 根據數量來完成
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 使用雙重否定來完成
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 使用雙重否定來完成
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、查詢各學生的年齡
--46.1 只按照年份來算
select
* , datediff(yy , sage , getdate()) [年齡]
from
student
--46.2 按照出生日期來算,當前月日 < 出生年月的月日則,年齡減一
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
[年齡]
from
student
--47、查詢本週過生日的學生
select
*
from
student
where
datediff(week,datename(yy,getdate()) +
right
(
convert
(
varchar
(10),sage,120),6),getdate()) = 0
--48、查詢下週過生日的學生
select
*
from
student
where
datediff(week,datename(yy,getdate()) +
right
(
convert
(
varchar
(10),sage,120),6),getdate()) = -1
--49、查詢本月過生日的學生
select
*
from
student
where
datediff(mm,datename(yy,getdate()) +
right
(
convert
(
varchar
(10),sage,120),6),getdate()) = 0
--50、查詢下月過生日的學生
select
*
from
student
where
datediff(mm,datename(yy,getdate()) +
right
(
convert
(
varchar
(10),sage,120),6),getdate()) = -1
drop
table
Student,Course,Teacher,SC