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