一句Sql把纵向表转为横向表，并分别分组求平均和总平均值

一句Sql把纵向表转为横向表，并分别分组求平均和总平均值，需要的朋友可以参考下。

declare @tab table(Class varchar(20),Student varchar(20),Course varchar(50),Quantity decimal(7,2)); 
insert into @tab(Class,Student,Course,Quantity) values('A班','张三','语文',60); 
insert into @tab(Class,Student,Course,Quantity) values('A班','张三','数学',70); 
insert into @tab(Class,Student,Course,Quantity) values('A班','张三','英语',80); 
insert into @tab(Class,Student,Course,Quantity) values('A班','李四','语文',30); 
insert into @tab(Class,Student,Course,Quantity) values('A班','李四','数学',40); 
insert into @tab(Class,Student,Course,Quantity) values('A班','李四','英语',50); 

insert into @tab(Class,Student,Course,Quantity) values('B班','王五','语文',65); 
insert into @tab(Class,Student,Course,Quantity) values('B班','王五','数学',75); 
insert into @tab(Class,Student,Course,Quantity) values('B班','王五','英语',85); 
insert into @tab(Class,Student,Course,Quantity) values('B班','赵六','语文',35); 
insert into @tab(Class,Student,Course,Quantity) values('B班','赵六','数学',45); 
insert into @tab(Class,Student,Course,Quantity) values('B班','赵六','英语',55); 



select * from @tab 

select 
(case when Grouping(Class)=1 then '总平均' when Grouping(Student)=1 then '' else Class end ) as Class 
,(case when Grouping(Class)=1 then '' when Grouping(Student)=1 then '平均' else Student end) as Student 
,avg(语文) as 语文 
,avg(数学) as 数学 
,avg(英语) as 英语 
,avg(总分) as 总分 
from ( 
select Class,Student 
,(select isnull(sum(Quantity),0) from @tab where Class=t.Class and Student=t.Student and Course='语文') as '语文' 
,(select isnull(sum(Quantity),0) from @tab where Class=t.Class and Student=t.Student and Course='数学') as '数学' 
,(select isnull(sum(Quantity),0) from @tab where Class=t.Class and Student=t.Student and Course='英语') as '英语' 
,(select isnull(sum(Quantity),0) from @tab where Class=t.Class and Student=t.Student) as '总分' 
from @tab as t 
group by Class,Student 
) as tempTab 
group by Class,Student,语文,数学,英语,总分 with rollup 
having Grouping(语文)=1 
and Grouping(数学)=1 
and Grouping(英语)=1