declare @sql varchar(8000)
select @sql = isnull(@sql + ',' , '') + Class from Elearning_AnswerSheet group by Class
exec ('select m.* , n.平均分 from
(select * from (select Store,Name,Code,Mark from Elearning_AnswerSheet) a pivot (AVG(Mark) for Class in (' + @sql + ')) b) m ,  
(select Store,Name,Code,avg(Mark) as 平均分 from Elearning_AnswerSheet group by Store,Name,Code) n 
   where m.Store = n.Store and m.Name=n.Name and m.Code=n.Code) tb ')


--try

------解决方案--------------------

SQL code
declare @sql varchar(8000)
select @sql = isnull(@sql + '],[' , '') +  Class from Elearning_AnswerSheet group by Class 
set @sql =  '[' + @sql + ']'
exec ('select m.* , n.平均分 from
(select * from (select Store,Name,Code,Mark from Elearning_AnswerSheet) a pivot (AVG(Mark) for Class in (' + @sql + ')) b) m ,  
(select Store,Name,Code,avg(Mark) as 平均分 from Elearning_AnswerSheet group by Store,Name,Code) n
where m.Store = n.Store and m.Name=n.Name and m.Code=n.Code')