摘要： 简单子查询select * from (select custid, companyname from Sales.Customers where country = N'USA') as USACusts关联子查询select custid, orderid, orderdate, empidfrom Sales.Orders as o1where orderid = (select max(o2.orderid) from Sales.Orders as o2 where o2.custid = o1.custid)select orderid, custid, val.. 阅读全文