如何用 lambda 表达式实现两张表的查询

select * from tcustomer where customerid in (select customerid from toperator where branchid=2 and iscustomerid=1 and state=1)

tcustomer.Where(x => toperator.Where(y => y.branchid ==2 && y.iscustomerid == 1 && y.state==1).Select(y => y. customerid).Contains(x.customerid))

linq也支持join的，参考下面贴中q107770540的回答
http://bbs.csdn.net/topics/390612385