Debug info: ORA-00918: column ambiguously defined

SELECT *

FROM (SELECT

ha.*, (ha.timemodified - ha.timestart) AS duration, (CASE WHEN gg.rawgrade IS NULL THEN 0 ELSE ROUND(gg.rawgrade, 0) END) AS grade, u.id AS userid,u.picture,u.firstname,u.lastname,u.imagealt,u.email

FROM m2hotpot_attempts ha INNER JOIN m2user u ON ha.userid = u.id LEFT JOIN m2grade_items gi ON gi.courseid = :o_courseid AND gi.itemtype = :o_itemtype AND gi.itemmodule = :o_itemmodule AND gi.iteminstance = :o_iteminstance LEFT JOIN m2grade_grades gg ON gg.itemid = gi.id AND gg.userid = ha.userid

WHERE ha.hotpotid=:o_hotpotid AND ha.userid=u.id

ORDER BY u.firstname, u.lastname, ha.attempt ASC)

WHERE rownum <= :o_oracle_num_rows

[array (

'o_courseid' => '42',

'o_itemtype' => 'mod',

'o_itemmodule' => 'hotpot',

'o_iteminstance' => '801',

'o_hotpotid' => '801',

'o_oracle_num_rows' => 30,

)]

Error code: dmlreadexception

Stack trace:

line 426 of /lib/dml/moodle_database.php: dml_read_exception thrown

line 274 of /lib/dml/oci_native_moodle_database.php: call to moodle_database->query_end()

line 1119 of /lib/dml/oci_native_moodle_database.php: call to oci_native_moodle_database->query_end()

line 1422 of /lib/tablelib.php: call to oci_native_moodle_database->get_records_sql()

line 162 of /mod/hotpot/report/renderer.php: call to table_sql->query_db()

line 98 of /mod/hotpot/report/renderer.php: call to mod_hotpot_report_renderer->reportcontent()

line 93 of /mod/hotpot/report.php: call to mod_hotpot_report_renderer->render_report()

$userfields = ', '.$this->get_userfields('u', null, 'userid');

$userfields = ', '.$this->get_userfields('u', null, 'userid2');