Hi

After installing the Ranking block i run admin/cron.php.

It stops when reach this error mesage about the ranking block. Is there any fix ?

Thank's in advance

Starting blocks
Processing cron function for ranking....... started 16:53:11. Current memory use 3.8MB.
!!! Error reading from database !!!
!! ERROR: function ifnull(bigint, integer) does not exist
LINE 6: cmc.id > (SELECT IFNULL(MAX(cmcid),0) FROM m...
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.
SELECT
cmc.id as cmcid, cmc.coursemoduleid, cmc.userid, cmc.timemodified as timecreated, cmc.timemodified
FROM
mdl_course_modules_completion cmc
WHERE
cmc.id > (SELECT IFNULL(MAX(cmcid),0) FROM mdl_ranking_cmc_mirror)
ORDER BY cmc.id
[array (
)]
Error code: dmlreadexception !!
!! Stack trace: * line 443 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 744 of /lib/dml/pgsql_native_moodle_database.php: call to pgsql_native_moodle_database->query_end()
• line 148 of /blocks/ranking/lib.php: call to pgsql_native_moodle_database->get_records_sql()
• line 119 of /blocks/ranking/lib.php: call to get_modules_completion_to_mirror()
• line 96 of /blocks/ranking/block_ranking.php: call to block_ranking_mirror_completions()
• line 323 of /lib/cronlib.php: call to block_ranking->cron()
• line 81 of /admin/cron.php: call to cron_run()