PHP/MYSQL Syntax question

Ok Im working on a php input script and need to use a mysql update statement so that records within a table can be updated but Im really having a hard time getting the server to except the statement. I am familiar with msql but in reguards to all the “quirky” sytax that you need to use between php and mysql Im running into problems. Heres and example of what Im trying to do if any of you can possibly help.

$insertSQL = sprintf("UPDATE authuser SET student_name, student_address, student_phone, student_ss, student_funding, student_agent, student_aproxcomp VALUES (%s, %s, %s, %s, %s, %s, %s) WHERE uname = 'student'", 
						   GetSQLValueString($_POST['student'], "text"), 
						   GetSQLValueString($_POST['course'], "text"), 
						   GetSQLValueString($_POST['completion'], "text"), 
						   GetSQLValueString($_POST['instructor'], "text"), 
						   GetSQLValueString($_POST['whenbilled'], "text"), 
						   GetSQLValueString($_POST['whenpaid'], "text"), 
						   GetSQLValueString($_POST['grade'], "int"));  

any help would be greatly appriciated!