Very simple request in MYSQL but getting no output

[CodGuru]

I have a very simple query to do and yet I can not, I am fine based on a book. I have two tables: "pages" and "users". In the Pages table, the fields author_id corresponds to id in the users table of the author of the page. "name" is the name of the table field that contains the users name.
Here's where I am:

  SELECT pages.author_id, users.name 
  FROM pages, users 
  WHERE pages.id = { $this->id } AND users.id = pages.author_id

No error from mysql but no return when the ID that I provided is correct. It is surely very simple but I do not understand the whole problem

[XSI]

Use a JOIN instead of a WHERE condition to join your two tables.

There you met WHERE MyTable.id = my_other_table.fk_id
Use rather FROM MyTable INNER JOIN my_other_table ON id = fk_id

[Lemog]

author_id is zero so it can not work

[fellah]

Use a JOIN instead of a WHERE condition to join your two tables.

There you met WHERE MyTable.id = my_other_table.fk_id
Use rather FROM MyTable INNER JOIN my_other_table ON id = fk_id

Why? Does it improves performance, or is it another reason?

[XSI]

Yes it improves performance as well as readability.