When I try to submit allocation in workshop (using ORACLE) I get this error:

Debug info: ORA-00904: “U”.”ID”: invalid identifier
SELECT u.id,u.picture,u.firstname,u.lastname,u.imagealt,u.email
FROM c_user u
JOIN (SELECT DISTINCT eu5_u.id
FROM c_user eu5_u JOIN c_role_assignments eu5_ra3 ON (eu5_ra3.userid = eu5_u.id AND eu5_ra3.roleid IN (5)
AND eu5_ra3.contextid IN (1,15,141,356))
JOIN c_groups_members eu5_gm ON (eu5_gm.userid = eu5_u.id AND eu5_gm.groupid = :o_eu5_gmid)
JOIN c_user_enrolments eu5_ue ON eu5_ue.userid = eu5_u.id
JOIN c_enrol eu5_e ON (eu5_e.id = eu5_ue.enrolid AND eu5_e.courseid = :o_eu5_courseid)
WHERE eu5_u.deleted = 0 AND eu5_u.id <> :o_eu5_guestid AND eu5_ue.status = :o_eu5_active AND
eu5_e.status = :o_eu5_enabled AND eu5_ue.timestart < :o_eu5_now1 AND (eu5_ue.timeend = 0 OR
eu5_ue.timeend > :o_eu5_now2)) je ON (je.id = u.id AND u.deleted = 0) JOIN c_workshop_submissions ws ON
(ws.authorid = u.id AND ws.example = 0 AND ws.workshopid = :o_workshopid6)
UNION
SELECT u.id,u.picture,u.firstname,u.lastname,u.imagealt,u.email
FROM c_user u
JOIN (SELECT DISTINCT eu6_u.id
FROM c_user eu6_u JOIN c_role_assignments eu6_ra3 ON (eu6_ra3.userid = eu6_u.id AND eu6_ra3.roleid IN
(5) AND eu6_ra3.contextid IN (1,15,141,356))
JOIN c_groups_members eu6_gm ON (eu6_gm.userid = eu6_u.id AND eu6_gm.groupid = :o_eu6_gmid) JOIN
c_user_enrolments eu6_ue ON eu6_ue.userid = eu6_u.id
JOIN c_enrol eu6_e ON (eu6_e.id = eu6_ue.enrolid AND eu6_e.courseid = :o_eu6_courseid)
WHERE eu6_u.deleted = 0 AND eu6_u.id <> :o_eu6_guestid AND eu6_ue.status = :o_eu6_active AND
eu6_e.status = :o_eu6_enabled AND eu6_ue.timestart < :o_eu6_now1 AND (eu6_ue.timeend = 0 OR
eu6_ue.timeend > :o_eu6_now2)) je ON (je.id = u.id AND u.deleted = 0)
JOIN c_workshop_submissions ws ON (ws.authorid = u.id AND ws.example = 0 AND ws.workshopid = :o_workshopid7)
ORDER BY u.lastname, u.firstname, u.id

[array (
'o_eu5_gmid' => 4,
'o_eu5_courseid' => '25',
'o_eu5_guestid' => '1',
'o_eu5_active' => 0,
'o_eu5_enabled' => 0,
'o_eu5_now1' => 1360757700,
'o_eu5_now2' => 1360757700,
'o_workshopid6' => '43',
'o_eu6_gmid' => 3,
'o_eu6_courseid' => '25',
'o_eu6_guestid' => '1',
'o_eu6_active' => 0,
'o_eu6_enabled' => 0,
'o_eu6_now1' => 1360757700,
'o_eu6_now2' => 1360757700,
'o_workshopid7' => '43',
)]

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 1101 of

/lib/dml/oci_native_moodle_database.php: call to oci_native_moodle_database→query_end() line 424 of

/mod/workshop/locallib.php: call to oci_native_moodle_database→get_records_sql() line 324 of

/mod/workshop/allocation/manual/lib.php: call to workshop→get_potential_authors() line 79 of

/mod/workshop/allocation.php: call to workshop_manual_allocator→ui()

Testing Instructions:
1) create a workshop
2) Set Group mode: Separate groups
3) Set Grouping: None
4) Click on Allocate submissions
5) Click on Manual allocation or Random allocation

I think that is problem is caused the usage of alias in the union.

I try to add a dummy alias in 2 functions: get_potential_authors and get_potential_reviewers)
in this way

list($sort, $sortparams) = users_order_by_sql('u');
$sql .= " ORDER BY $sort";

$sql = "SELECT * FROM (".$sql;
list($sort, $sortparams) = users_order_by_sql('uu');
$sql .= ")uu ORDER BY $sort";

In this way it seems to work but I'm not sure that this solution is correct.

Any confirm?