Debug info: ERROR: syntax error at or near "'customfield_firstdate'"

LINE 1: SELECT u.*, cf0.data AS 'customfield_firstdate' , u.lastname...

^

SELECT u.*, cf0.data AS 'customfield_firstdate' , u.lastname AS usrt1, u.firstname AS usrt2, u.id AS usrt

FROM mdl_user u

JOIN (SELECT DISTINCT eu1_u.id

FROM mdl_user eu1_u

JOIN mdl_user_enrolments eu1_ue ON eu1_ue.userid = eu1_u.id

JOIN mdl_enrol eu1_e ON (eu1_e.id = eu1_ue.enrolid AND eu1_e.courseid = $1)

WHERE eu1_u.deleted = 0 AND eu1_u.id <> $2 AND eu1_ue.status = $3 AND eu1_e.status = $4 AND eu1_ue.timestart < $5 AND (eu1_ue.timeend = 0 OR eu1_ue.timeend > $6)) je ON je.id = u.id

LEFT JOIN (SELECT * FROM mdl_user_info_data

WHERE fieldid = $7) cf0

ON u.id = cf0.userid

JOIN (

SELECT DISTINCT ra.userid

FROM mdl_role_assignments ra

WHERE ra.roleid = $8

AND ra.contextid IN ($9,$10,$11)

) rainner ON rainner.userid = u.id

WHERE u.deleted = 0

ORDER BY usrt1 ASC, usrt2 ASC, usrt ASC

[array (

0 => '2',

1 => '1',

2 => 0,

3 => 0,

4 => 1380092900,

5 => 1380092900,

6 => '1',

7 => '5',

8 => '41',

9 => '3',

10 => '1',

)]

Error code: dmlreadexception

Stack trace:

    line 436 of /lib/dml/moodle_database.php: dml_read_exception thrown

    line 239 of /lib/dml/pgsql_native_moodle_database.php: call to moodle_database->query_end()

    line 702 of /lib/dml/pgsql_native_moodle_database.php: call to pgsql_native_moodle_database->query_end()

    line 214 of /grade/lib.php: call to pgsql_native_moodle_database->get_recordset_sql()

    line 244 of /grade/export/lib.php: call to graded_users_iterator->init()

    line 62 of /grade/export/txt/index.php: call to grade_export->display_preview()