ORA-00918: column ambiguously defined

SELECT *

FROM (SELECT u.*, ci.code, ci.timecreated

FROM m_user u

INNER JOIN m_certificate_issues ci

ON u.id = ci.userid

WHERE ci.certificateid = :o_certificateid

ORDER BY firstname || ' ' || lastname )

WHERE rownum <= :o_oracle_num_rows

[array (

'o_certificateid' => '142',

'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 1101 of /lib/dml/oci_native_moodle_database.php: call to oci_native_moodle_database->query_end()

    line 729 of /mod/certificate/lib.php: call to oci_native_moodle_database->get_records_sql()

    line 92 of /mod/certificate/report.php: call to certificate_get_issues()