相关子查询的使用

本文介绍了相关子查询的使用的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

即使它有性能问题，我是否也可以知道相关子查询的用途?

Even though It has a performance issue, may I know what is the use of correlated subquery?

推荐答案

首先，它没有性能问题.就是这样，鉴于硬件和数据库结构的性能限制，它将尽可能地执行.

Well, firstly it doesn't have a performance issue. It is what it is, and it will be executed as well as possible given the performance constraints of the hardware and database structure.

关于它的作用，它只是表达特定逻辑条件的一种方式.

As for what it is useful for, it is just a way of expressing particular logical conditions.