exec('select '+@getavg+' = avg('+@a+') from buguding')

declare @getavg decimal(18,4),@a sysname
--@a賦值略
declare @s nvarchar(4000)

set @s='select @getavg = avg('+@a+') from buguding'

exec sp_executesql @s,N'@getavg decimal(18,4) output',@getavg output
select @getavg

------解决方案--------------------
SQL code

create table test0722(id int)
insert into test0722 select 10 union all select 20

declare @getavg varchar(20) set @getavg='newcolname'
declare @a varchar(20) set @a='id'

exec('select '+@getavg+' = avg('+@a+') from test0722')
/*
newcolname
-----------
15
*/

------解决方案--------------------
楼主是要得到变量值输出，不是要传入别名，那就需要用sp_executesql了
SQL code

declare @a int;
declare @sql nvarchar(4000);
set @a=1;
SET @sql='select @b  set @b=@b+1 select @b';

exec sp_executesql @sql, N'@b int output', @b=@a;

------解决方案--------------------
declare @aa int  
exec sp_executesql N'select @a=SUM(d) from table_1',N'@a int out',@aa out
print @aa
按照这个模式来。。。