各位高手,请帮帮忙!!!!!在线等@!谢谢!!!

以下这句话,我该如何写呢????
if   not   exists(select   *   from   @tabname   where   material_id=@materialid)

谢谢!!!

------解决方案--------------------
放在同一个变量里,这样试一下

declare @sql varchar(8000)
set @sql= 'if not exists(select * from '+@tabname+ ' where material_id= '+rtrim(@materialid)
print(@sql+ '
insert into '+@tabname+ '(material_id,levelonecode,levelonename,leveltwocode,leveltwoname,levelthreename)
values( ' ' '+@materialid+ ' ' ', ' ' '+@onematerialcode+ ' ' ', ' ' '+@onematerialname+ ' ' ', ' ' '+@twomaterialcode+ ' ' ', ' ' '+@twomaterialname+ ' ' ', ' ' '+@threematerialname+ ' ' ')
')

------解决方案--------------------
declare @sql varchar(8000)
set @sql= 'if not exists(select 1* from '+@tabname+ ' where material_id= '+rtrim(@materialid)
exec(@sql)