行列转置加平均值,该怎么解决_Sql Server

行列转置加平均值
请大家给我看下以下语句为何报错，谢谢大家了！
消息 102，级别 15，状态 1，第 2 行
'/' 附近有语法错误。
消息 102，级别 15，状态 1，第 3 行
'n' 附近有语法错误。

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')

------解决方案--------------------

SQL code

declare @sql varchar(8000)select @sql = isnull(@sql + ',' , '') + Class from Elearning_AnswerSheet group by Classexec ('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 codedeclare @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) nwhere m.Store = n.Store and m.Name=n.Name and m.Code=n.Code')