sql

sql统计－关于学生成绩 

学生成绩表(stuscore)：

姓名：name
课程：subject
分数：score
学号：stuid

张三
数学
89
1

张三
语文
80
1

张三
英语
70
1

李四
数学
90
2

李四
语文
70
2

李四
英语
80
2



创建表
SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

SET ANSI_PADDING ON

GO

CREATE TABLE [dbo].[stuscore](

    [name] [varchar](50) COLLATE Chinese_PRC_CI_AS NULL,

    [subject] [varchar](50) COLLATE Chinese_PRC_CI_AS NULL,

    [score] [int] NULL,

    [stuid] [int] NULL

) ON [PRIMARY]



GO

SET ANSI_PADDING OFF


问题：

1.    计算每个人的总成绩并排名(要求显示字段：姓名，总成绩)

2.    计算每个人的总成绩并排名(要求显示字段: 学号，姓名，总成绩)

3.    计算每个人单科的最高成绩(要求显示字段: 学号，姓名，课程，最高成绩)

4.    计算每个人的平均成绩（要求显示字段: 学号，姓名，平均成绩）

5.    列出各门课程成绩最好的学生(要求显示字段: 学号，姓名,科目，成绩)

6.    列出各门课程成绩最好的两位学生(要求显示字段: 学号，姓名,科目，成绩)

7.    统计如下：

学号
姓名
语文
数学
英语
总分
平均分


 
 
 
 
 
 




8．列出各门课程的平均成绩（要求显示字段：课程，平均成绩）

9．列出数学成绩的排名（要求显示字段：学号，姓名，成绩，排名）

10．列出数学成绩在2-3名的学生（要求显示字段：学号，姓名,科目，成绩）

11．求出李四的数学成绩的排名

12．统计如下：

课程
不及格（0-59）个
良（60-80）个
优（81-100）个


 
 
 

  



13．统计如下：数学:张三(50分),李四(90分),王五(90分),赵六(76分)

答案：


1.       计算每个人的总成绩并排名


select name,sum(score) as allscore from stuscore group by name order by allscore


2.   计算每个人的总成绩并排名


select distinct t1.name,t1.stuid,t2.allscore from  stuscore t1,

(

    select stuid,sum(score) as allscore from stuscore group by stuid

)t2

where t1.stuid=t2.stuid

order by t2.allscore desc

3. 计算每个人单科的最高成绩


select t1.stuid,t1.name,t1.subject,t1.score from stuscore t1,

(

select stuid,max(score) as maxscore from stuscore group by stuid

) t2

where t1.stuid=t2.stuid and t1.score=t2.maxscore

4.计算每个人的平均成绩


select distinct t1.stuid,t1.name,t2.avgscore from stuscore t1,

(

select stuid,avg(score) as avgscore from stuscore group by stuid

) t2

where t1.stuid=t2.stuid

5.列出各门课程成绩最好的学生


select  t1.stuid,t1.name,t1.subject,t2.maxscore from stuscore t1,

(

select subject,max(score) as maxscore from stuscore group by subject

) t2

where t1.subject=t2.subject and t1.score=t2.maxscore


6.列出各门课程成绩最好的两位学生


select distinct t1.* from stuscore t1

where t1.stuid in

(select top 2 stuscore.stuid from stuscore where subject = t1.subject order by score desc)

order by t1.subject



7.学号    姓名    语文     数学     英语     总分  平均分


select stuid as 学号,name as 姓名,

sum(case when subject='语文' then score else 0 end) as 语文,

sum(case when subject='数学' then score else 0 end) as 数学,

sum(case when subject='英语' then score else 0 end) as 英语,

sum(score) as 总分,(sum(score)/count(*)) as 平均分

from stuscore

group by stuid,name

order by 总分desc

8.列出各门课程的平均成绩


select subject,avg(score) as avgscore from stuscore

group by subject

9.列出数学成绩的排名


declare @tmp table(pm int,name varchar(50),score int,stuid int)

insert into @tmp select null,name,score,stuid from stuscore where subject='数学' order by score desc

declare @id int

set @id=0;

update @tmp set @id=@id+1,pm=@id

select * from @tmp




select  DENSE_RANK () OVER(order by score desc) as row,name,subject,score,stuid from stuscore where subject='数学'

order by score desc

declare @tmp table(pm int identity(1,1),name varchar(50),score int,stuid int)
insert into @tmp
select name,score,stuid from stuscore where subject='数学' order by score desc
select * from @tmp

10. 列出数学成绩在2-3名的学生


select t3.*  from

(

select top 2 t2.*  from (

select top 3 name,subject,score,stuid from stuscore where subject='数学'

order by score desc

) t2 order by t2.score

) t3 order by t3.score desc

11. 求出李四的数学成绩的排名


declare @tmp table(pm int,name varchar(50),score int,stuid int)

insert into @tmp select null,name,score,stuid from stuscore where subject='数学' order by score desc

declare @id int

set @id=0;

update @tmp set @id=@id+1,pm=@id

select * from @tmp where name='李四'

12. 课程    不及格（-59）   良（-80）   优（-100）
select subject,

(select count(*) from stuscore where score<60 and subject=t1.subject) as 不及格,

(select count(*) from stuscore where score between 60 and 80 and subject=t1.subject) as 良,

(select count(*) from stuscore where score >80 and subject=t1.subject) as 优

from stuscore t1 group by subject
13. 数学:张三(50分),李四(90分),王五(90分),赵六(76分)
declare @s varchar(1000)

set @s=''

select @s =@s+','+name+'('+convert(varchar(10),score)+'分)' from stuscore where subject='数学'

set @s=stuff(@s,1,1,'')

print '数学:'+@s