LEFT JOIN problem

[bpgillett]

hi.  i have two tables .  one table, 'competency_actions', has the unique id's for different actions ('action_id') and the action names ('action').  the other table, 'competency_log', has fields about these actions and the unique id's for the students ('r_id') who completed them.  some actions are required and have the field, 'required', set to 1 in the 'competency_actions' table.  i am trying to select any required actions from table 'competency_actions' that are not present in table 'competency_log' for a given student ('r_id').  i can't figure out how to limit the query to a particular student as 'r_id' is null in my LEFT JOIN.  here's what i have so far with out specifying the 'r_id':

 

$result1 = mysql_query(

[Barand]

Well, that's a start

 

SELECT a.action
FROM competency_actions a
LEFT JOIN comptency_log l ON a.action_id = l.action_id and r_id = '$studentID'
WHERE a.reuired = 1 
AND l.action_id IS NULL