SELECT DISTINCT ue.id, ue.userid, e.courseid
              FROM {user_enrolments} ue
              JOIN {enrol} e ON e.id = ue.enrolid
              JOIN {course} c ON c.id = e.courseid JOIN {user} u ON u.id = ue.userid WHERE e.courseid <> :siteid
               AND c.visible = 1 AND ue.status = :active
                 AND e.status = :enabled
                 AND ue.timestart < :now1
                 AND (ue.timeend = 0 OR ue.timeend > :now2)
records: Array
(
    [2] => stdClass Object
        (
            [id] => 2
            [userid] => 3
            [courseid] => 3
        )

    [3] => stdClass Object
        (
            [id] => 3
            [userid] => 4
            [courseid] => 2
        )

    [4] => stdClass Object
        (
            [id] => 4
            [userid] => 5
            [courseid] => 2
        )

    [1] => stdClass Object
        (
            [id] => 1
            [userid] => 3
            [courseid] => 2
        )

)

SELECT COUNT(*)
              FROM (SELECT DISTINCT ue.userid, e.courseid
              FROM {user_enrolments} ue
              JOIN {enrol} e ON e.id = ue.enrolid
              JOIN {course} c ON c.id = e.courseid JOIN {user} u ON u.id = ue.userid WHERE e.courseid <> :siteid
               AND c.visible = 1 AND ue.status = :active
                 AND e.status = :enabled
                 AND ue.timestart < :now1
                 AND (ue.timeend = 0 OR ue.timeend > :now2) ) total
enrols: 0