I'm writing a block in PHP for Moodle 3.2 and I'm having a little difficulty with the SQL not working.

Basically I want to get the quiz scores for all users on a course for all the quizzes.

My SQL works in phpMyAdmin

SELECT u.id, u.firstname, u.lastname, qg.quiz, qg.grade, 
     q.grade as maxgrade, q.name 
FROM mdl_quiz_grades qg 
JOIN mdl_user u ON u.id = qg.userid 
JOIN mdl_quiz q ON q.id = qg.quiz 
WHERE q.course = 2 

As I say this working in MySQL:

However here is the PHP code in Moodle:

$sql = "
SELECT  u.id, u.firstname, u.lastname, 
        qg.quiz, qg.grade, q.grade AS maxgrade, q.name 
FROM {quiz_grades} qg 
JOIN {user} u ON u.id = qg.userid 
JOIN {quiz} q ON q.id = qg.quiz 

WHERE q.course = ?"; 
$params = array($COURSE->id);**//NB Course ID is 2**
$records = $DB->get_records_sql($sql, $params);
print_r($records);

Which produces only the two records where the QUIZ id is also 2.

Array ( [5] => stdClass Object ( [id] => 5 [firstname] => Bart [lastname] => Simpson [quiz] => 2 [grade] => 5.00000 [maxgrade] => 10.00000 [name] => Quiz 2 ) [6] => stdClass Object ( [id] => 6 [firstname] => Lisa [lastname] => Simpson [quiz] => 2 [grade] => 5.00000 [maxgrade] => 10.00000 [name] => Quiz 2 ) )

I'm unclear where I have gone wrong but also why I get two different results

Any advice cheerfully received,

Many Thanks

Dave