Did you remember to make the first column something unique in your call to get_records? Duplicate value 'xxxxxx' found in column 'course'.* line 1014 of /lib/dml/mysqli_native_moodle_database.php: call to debugging()

* line 1493 of /mod/assign/locallib.php: call to mysqli_native_moodle_database->get_records_sql()

* line 859 of /mod/assign/lib.php: call to assign::cron()

* line 267 of /lib/cronlib.php: call to assign_cron()

* line 61 of /admin/cli/cron.php: call to cron_run()

	        $sql = 'SELECT a.course, a.name, a.blindmarking, a.revealidentities,

	                       g.*, g.id as gradeid, g.timemodified as lastmodified

	                 FROM {assign} a

	                 JOIN {assign_grades} g ON g.assignment = a.id

	                 LEFT JOIN {assign_user_flags} uf ON uf.assignment = a.id AND uf.userid = g.userid

	                WHERE g.timemodified >= :yesterday AND

	                      g.timemodified <= :today AND

	                      uf.mailed = 0';

function assignment_get_unmailed_submissions($starttime, $endtime) {

	    global $CFG, $DB;

	    return $DB->get_records_sql("SELECT s.*, a.course, a.name

	                                   FROM {assignment_submissions} s,

	                                        {assignment} a

	                                  WHERE s.mailed = 0

	                                        AND s.timemarked <= ?

	                                        AND s.timemarked >= ?

	                                        AND s.assignment = a.id", array($endtime, $starttime));

}