如何写这样的SQL 的语句？

[rainlow]

有一张表A，里面存放了一些书的信息（bookname,author--作者,price...），现在要选出author写过两本以上几上的书籍.

[lsxaa]

select * from 表 aa where (select count(*) from 表 where author=aa.author)>=2

[zlj113]

select * from u_table where author=(select author from u_table group by author having count(*)>2)


想当然写的，没测试，错了不负责：）

[Andy__Huang]

select author from tb group by author having count(author)>=2

[yyhyy23]

select author from tb group by author having count(author)>=2

[zhangzs8896]

select a.* from 表 a
inner join (select author from 表 group by author having count(author)>=2)b
on a.author=b.author