理学 数据库系统 释 query optimization 查询优化 查询优化旨在通过选择有效策略，对给定的关系表达式求值，使得查询代价最小。
数据库 数据库管理系统及其实现技术 释文 query optimization 查询优化
- Port of Tokyo
- Port of Tongjiang
- Port of Tubarao
- Port of Vancouver
- Port of Wenzhou
- Port of Wuhan
- Port of Wuhu
- Port of Wuxi
- Port of Wuzhou
- Port of Xiamen
- Port of Xunke
- Port of Yichang
- Port of Yokohama
- Port of Yueyang
- Port of Zhanjiang
- Port of Zhaoqing
- Port of Zhenjiang
- Port of Zhuhai
- Porto-Novo
- portosystemic shunts
- Port Pirie
- port production organization
- port production targets
- port project construction
- Port Qasim