Need help with Mysql query

ok i have three tables

post table
-----------------
post_id --- category_id --- author_id -- content --- ect


categories table
-----------------
category_id --- category_name


users table
------
author_id --- username --- pw


whats the best way to query posts and fetch the related category_name and username with the post? how would i do it?

should i do three separate select queries? or is there a better way? performance wise

JOINs are a wonderful thing. See http://sqlcourse2.com/joins.html

SELECT
post_id,
content,
category_name,
username

FROM
tbl_post,
tbl_category,
tbl_users

WHERE
tbl_post.category_id = tbl_category.category_id
AND
tbl_post.author_id = tbl_users.author_id..

Should do the trick....