数据库笛卡尔积的相关内容

文章 2024-06-26 来自：开发者社区

技术心得：数据库之笛卡尔积

" 1. 什么是笛卡尔积 1.1 定义笛卡尔积又叫笛卡尔乘积，是一个叫笛卡尔的人提出来的。简单的说就是两个集合相乘//代码效果参考：https://v.youku.com/v_show/id_XNjQwMDM3NjE2MA==.html 的结果。具体的定义去看看有关代数系的书的定义。直观的说就是集合A{a1,a2,a3} 集合B{b1,b2} ...

文章 2024-06-06 来自：开发者社区

MySQL数据库——多表查询（1）-多表关系（一对多、多对对多、一对一）、多表查询概述（概念、笛卡尔积、分类）

多表查询多表关系多表查询概述内连接外连接自连接子查询多表查询案例概述项目开发中，在进行数据库表结构设计时，会根据业务需求及业务模块之间的关系，分析并设计表结构，由于业务之间相互关联，所以各个表结构之间也存在着各种联系，基本上分为三种：一对多（多对一） ...

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更新时间 2024-06-27 10:00:24

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