MySQL to select friends/contact list??

I'm making a site where each user has a contact list (of other users on the site).
The database looks something like:

Users:
-user_id
-username
etc..

Contacts:
-id
-account_id
-contact_id

The problem is the mysql query used to select the contact list for a user..

say I wanted to list all contacts of a user -by username, not ID.
At the moment I have:

$getcontacts = mysql_query("SELECT * FROM contacts WHERE account_id='$userid'");
while($contact = mysql_fetch_assoc($getcontacts)){
 $getuser = mysql_query("SELECT username FROM users WHERE user_id='$contact[contact_id]'");
 $user = mysql_fetch_assoc($getuser);
 echo $user[username].'<br />';
}

PHP:

it works.. but isn't doing a seperate query for each contact really inefficient or something?
How would this normally be done? or would it use a different structure for the db?

 

Use JOIN

SELECT users.username FROM users 
INNER JOIN contacts ON users.user_id = contacts.account_id
WHERE contacts.account_id='$userid'

PHP:

 

Ah, thanks for the help!
I'll look into it

 

You are weclome