原文:SQL点滴35-SQL语句中的exists 比如在Northwind数据库中有一个查询为 SELECT c.CustomerId,CompanyName FROM Customers c WHERE EXISTS( SELECT OrderID FROM Orders o WHERE o.CustomerID=c.CustomerID) 这里面的EXISTS是如何运作呢?子查询返回的是OrderId字段,可是外面的查询要找的是CustomerID和CompanyName字段,这两个字段肯定
測试oracle 11g cluster 中OLR的重要性 called an Oracle Local Registry (OLR): each node in a cluster has a local registry for node-specific resources 測试一:模拟olr异常丢失的情况: 这里首先将olr renam [root@vmrac2 cdata]# mv vmrac2.olr vmrac2.olr.bak 然后尝试去启动crs [root@vmrac2
7-4 Cartesian Tree (30分) A Cartesian tree is a binary tree constructed from a sequence of distinct numbers. The tree is heap-ordered, and an inorder traversal returns the original sequence. For example, given the sequence { 8, 15, 3, 4, 1, 5, 12, 1
1064 Complete Binary Search Tree (30 分) A Binary Search Tree (BST) is recursively defined as a binary tree which has the following properties: The left subtree of a node contains only nodes with keys less than the node's key. The right subtree of a