MySQL如何在两个字段上联接表 [英] MySQL how to join tables on two fields
本文介绍了MySQL如何在两个字段上联接表的处理方法,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
我有两个带有date
和id
字段的表.我想同时参加这两个领域.我尝试过
I have two tables with date
and id
fields. I want to join on both fields. I tried
JOIN t2 ON CONCAT(t1.id, t1.date)=CONCAT(t2.id, t2.date)
可以,但是非常慢.有更好的方法吗?
that works, but it is very slow. is there a better way to do this?
推荐答案
JOIN t2 ON t1.id=t2.id AND t1.date=t2.date
这篇关于MySQL如何在两个字段上联接表的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文