摘要: 比如在Northwind数据库中有一个查询为SELECT c.CustomerId,CompanyName FROM Customers cWHERE EXISTS(SELECT OrderID FROM Orders o WHERE o.CustomerID=c.CustomerID) 这里面的E 阅读全文
posted @ 2022-01-05 14:19 紫陌红尘520 阅读(1153) 评论(0) 推荐(0) 编辑