例子：
Tab1：id，name，pass...
Tab2:sn,tel,address...
Tab1 里的id 与 Tab2里的sn对应。
查询语句
select * from Tab1 as t1 join Tab2 as t2 on t1.id=t2.sn
这样查询出来会有重复，看下面这句
select top 10 id,name,pass,tel from Tab1 join Tab2 on Tab1.id=Tab2.sn where date_post between 2009/7/14 and 2009/10/21 group by Tab1.id,name,pass,Tab2.tel