谁能帮小弟看看能不能这么写啊？

alter proc


 @signal varchar (40),
 @unitid  varchar(10) ,
@date varchar(10),
@parkname varchar(10)

as
declare @sql varchar (4000)

set @sql='select a.*,b.avg_park
from
(select TTimeStampLocal,'+@signal+'from aa.vw10MinVMP where UnitId = '+@unitid+' and TTimeStampLocal>'''+@date+''') a
     inner join
 (select AVG( '+@signal+') as avg_park,TTimeStampLocal from aa.vw10MinVMP where ParkName= '''+@parkname+''' and TTimeStampLocal > '''+@date+''') b
 on a.TTimeStampLocal=b.TTimeStampLocal'
  exec (@sql)
以上修改成功。

执行以下命令
exec
@signal = 'Gen_Phase1_Temp_Avg',
@unitid='30005',
@date='2012-11-10',
@parkname='site'
——————————————————————————
报错：
Msg 102, Level 15, State 1, Line 3
Incorrect syntax near '.'.
Msg 102, Level 15, State 1, Line 5
Incorrect syntax near 'b'.