Join or use multiple arrays

[Drummin]

I have code that queries two tables for example...

$checkfordue = mysql_query("SELECT stuID FROM ".$conf['tbl']['homework']." , ".$conf['tbl']['homeworktable']." WHERE ".$conf['tbl']['homework'].".TID = '$newID' && ".$conf['tbl']['homeworktable'].".TID = '$newID' && ".$conf['tbl']['homeworktable'].".ID = '$ID' &&
".$conf['tbl']['homework'].".turnin = '2' && ".$conf['tbl']['homework'].".homeworkID = ".$conf['tbl']['homeworktable'].".ID ORDER BY stufirstname, stulastname");
WHILE($checkdue = mysql_fetch_array($checkfordue)) {etc

And the above code has been working fine.  The question really is about using JOIN instead of what I did.  And if you could please explain join left as well.  What are the benefits of using join rather then writing the query like I did.

[fugix]

a join can be used to join two or more tables together either where fields of different tables are equal or not... look here