php - How do I list related blog posts ordered by the number of common tags? -

I want to display a list of related blog posts and I want the list of common tags in those lists For the current post, each post can have several tags with it. Here's my table structure:

[post] & lt; - [Posts-to-tag-joining-table] -> [Tag]

I have PHP and MySQL - can I do this in a query?

what about ...:

  SELECT COUNT ( *) Post as post, post, post posts, post poster P2T on P2T PID. In PdTPID, in P2 TTD (PATT select P2T Inner Post Post on POT .pd = Post.Pid Where Posts Pid = 1) and Postpaid! = 1 are posted by group posts. Assuming PID as the primary key in the Designation table,  

As the primary key in the tag table, what's the foreign key in the p2t (post tag) table?