题目内容
建立索引需要额外的存储代价，但使用索引扫描一定比简单的全表扫描效率要高。
查看答案
搜索结果不匹配？点我反馈
更多问题
关系数据库管理系统查询处理4个阶段的执行顺序为（ ）
Hello, everybody! On behalf of the hotel, I’d like to express our warmest welcome to you. We do hope all our (1)____________will feel happy and comfortable here. We would be pleased to provide (2)__________ services to meet your needs. Here you can find many convenient facilities for you to use, such as a (3)_________, a healthy club and an indoor swimming poor. We also have three restaurants (4)_________ Chinese and Western foods, two bars and a large shopping center. Any suggestions for (5)_______ our service are welcome. Thank you for your attention.
Ladies and gentlemen, our plane is flying smoothly now. The duty- free sales will soon begin. Please (1)_____________ your list of purchase. In your seat pocket, you can find the Shopping on Board magazine, All prices are listed both in the local currency and in US dollars. And you can pay (2)__________ or by using a credit card. We accept (3)_________ major credit cards. Frequent passengers win points (4)_________ on board. There are some excellent bargains and there are several items specially designed for our (5)___________. Thank you.
说明：假定你是经理 Tim Huston，代表公司写一份欢迎信给新来的同事 Jessica Smith.内容：1、对Jessica Smith表示欢迎； Jessica Smith 是个优秀设计师，公司很幸运有她的加入；2、公司的其他人都很能干，也很友善，希望Jessica Smith在本公司工作愉快；3、有什么需要帮助，请告知。Words for refernece: 能干的 capable
微信支付 
支付宝支付