Sql Relationship problem

Iam tryin to place a live forum update colom on my page using php.

From using a yabbse board it has left me with numerous tables in my database.

By using 1 of the tables iam able to get the right url: But i need to reference it with another table so i can the subject correct aswell:

$dbcnx = @mysql_connect('localhost', 'root', '');
if (!$dbcnx) {
die( 'Unable to connect to the ' .
'database server at this time.' );
}

if (! @mysql_select_db('yabb') ) {
die( 'Unable to locate the Yabbse ' .
'database at this time.' );
}

$sql = "SELECT * FROM yabbse_topics ORDER BY ID_FIRST_MSG DESC";

$result=mysql_query($sql);

$num=mysql_numrows($result);

$i=0;
while ($i < 4) {

$boardId=mysql_result($result,$i,"ID_BOARD");
$msgId=mysql_result($result,$i,"ID_FIRST_MSG");
$topID=mysql_result($result,$i,"ID_TOPIC");

echo "<a href=http://www.%%%%%%.co.uk/yabbse/index.php?board=$boardId;action=display;threadid=$topID>Forum Subject: $boardId</a> ";

++$i;
}
?>