MySQL多表联接

本文介绍了MySQL多表联接的处理方法，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

我需要修改以下MySQL语句以包含来自第三张表的信息...但是我很迷恋联接.

I need to modify the following MySQL statement to include information from a third table... but I suck at joins.

select ss.*, se.name as engine, ss.last_run_at + interval ss.refresh_frequency day as next_run_at, se.logo_name from searches ss join search_engines se on ss.engine_id = se.id where ss.user_id='.$user_id.' group by ss.id order by ss.project_id, ss.domain, ss.keywords

我还需要包括通过将searches.project_id与projects.id匹配来检索projects.project_name.

I need to also include retrieving projects.project_name by matching searches.project_id to projects.id.

推荐答案

查看 SELECT语法和 JOIN语法.

Check out SELECT Syntax and JOIN Syntax.

但是，最简单的答案-添加另一个JOIN..ON语句.

But, simplest answer -- add another JOIN..ON statement.

select ss.*, se.name as engine, ss.last_run_at + interval ss.refresh_frequency day as next_run_at, se.logo_name, pr.project_name -- + from searches ss join search_engines se on ss.engine_id = se.id join projects pr on ss.project_id = pr.id -- + where ss.user_id='.$user_id.' group by ss.id order by ss.project_id, ss.domain, ss.keywords

[编辑]，我添加了-- +注释以指出我的添加内容.

[EDIT] I added the -- + comments to point out my additions.