两个表SQL双连接？

Question

I have two tables, sections and articles. Originally it was a one-to-many relationship, therefore articles has a sectionID column. Then one day it was decided to allow each article to belong to two sections. Rather than making another 'articles-in-section' table, I opted to not deal with refactoring the data, and I just added an additionalSectionID column onto the articles table. Now I have a problem.

I want to show all the articles associated with a given section, whether as its primary or secondary section. Essentially, I'm looking for some sort of double join between two tables.

These two questions have answers to the same issue - 1,2, but with a different db server. Is there are a way to do this in PHP/MySQL?

Tables' structure is basically like this:

-- SECTIONS:
id   title   description   moderatorID   url

-- ARTICLES: 
id   title   shortDesc     fullText      photo   sectionID   additionalSectionID

Answer 1

See below.

SELECT s.*, a.*
FROM sections s
LEFT JOIN articles a
ON s.id = a.sectionID
OR s.id = a.additionalSectionID
WHERE s.title = 'My Section';