左联接与左外联接之间的区别

本文介绍了左联接与左外联接之间的区别的处理方法，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

我想知道mySQL中的LEFT JOIN和LEFT OUTER JOIN是否有任何区别.如果没有区别，那为什么有两种不同的方式呢?

I want to know if there is any difference in LEFT JOIN and LEFT OUTER JOIN in mySQL. And if there is no difference then why two different ways are there?

预先感谢...

推荐答案

它们是相同的，我想将外部"放入其中的唯一原因是为了清楚起见，以便澄清其中的第一个表该联接不需要在第二个表中有要联接的东西.

They are the same, the only reason you would want to put the 'outer' in is for clarity I think, in order to clarify that the first table in the join does not require that it has something to join to in the second table.

这是一篇有关Wikipedia的好文章，涵盖了其中的一些内容.

从功能上讲，它们是相同的.

Functionally they are the same.