sql 统计 关于学生成绩

文章来源于：http://www.cnblogs.com/tenghoo/archive/2007/06/11/779240.html

学生成绩表(stuscore)：

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：

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：

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) 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