Simplify SQL Query

[BigChief]

Wondering if anyone can simplify this query for me please?

 

// $skillset = mysql_query("SELECT skillsetid FROM assigncourses WHERE userid='".$id."'")
// $skillset2 = mysql_query("SELECT cid FROM cidsid WHERE sid='".$skillset."'")
// $skillset3 = mysql_query("SELECT coursename FROM courses WHERE cid='".$skillset2."'")

 

I have another piece of SQL that works however I can't seem to get it to work in this instance even when I change the code to suit what I need.

 

$user = mysql_query("SELECT * FROM (assigncourses LEFT JOIN users on assigncourses.userid = users.id) LEFT JOIN skillsets on assigncourses.skillsetid = skillsets.skillid WHERE assigncourses.userid='".$id."' AND assigncourses.skillsetid > '0'");