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04 2017 档案

[SQL]SQL中EXISTS的用法

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 @ 2017-04-26 11:34 beeone 阅读(269) 评论(0) 推荐(0)