--try
select @sqlstr='select viastation from tmp_sche where scheduleid='''+@code+''''
exec @sqlstr
select @sqlstr='select viastation from tmp_sche where scheduleid='''+@code+''''
exec @sqlstr
set @sqlstr=''
select @sqlstr='select viastation from tmp_sche where scheduleid='''+@code+'''
exec(@sqlstr)