database - Best way to store a many-to-many relationship in MySQL?

Question

Let's say I have a simple database with tables 'posts' and 'tags'. Posts can have many tags and tags can belong to many posts.

What is the best way to structure the database? I thought of using a list/serialize:

tags
idx tag_id, str tag_name

posts
idx post_id, str title, list tag_ids

OR having another table with the associations. Problem is using this I don't even know how to structure the query to pull the associated tag names when I get a post.

posts
idx post_id, str title

post_tags
fk post_id, fk tag_id

I actually I don't like either of them. Is there a better way?

Answer 1

The post_tags is the proper means of implementing a many to many relationship in the database.

The only addition I'd make to what you posted is that both columns in it should be the primary key to ensure there are no duplicates.