When we setup assignments to different groups, we can view assignments . But if we choose a group, we got error message "No users were found with permissions to submit this assignment". I tracked the source code and found the problem is in the file accesslib.php in moodle lib directory. in function get_users_by_capability, because of our site settings, it went through the code
if ($defaultroleinteresting) {
$sql = "SELECT $fields
FROM {$CFG->prefix}user u
$uljoin
$where
ORDER BY $sort";

return get_records_sql($sql, $limitfrom, $limitnum);
}
I displayed the sql statement, it shows
SELECT u.id FROM mdl_user u WHERE u.deleted = 0 AND (ra.userid IN (SELECT userid FROM mdl_groups_members gm WHERE gm.groupid = 1)) ORDER BY u.lastaccess

the problem is ra.userid in the statement, there is no table alias is ra, so I tracked down where it came from. It is still in the same function. the code is
if ($groups) {
if (is_array($groups))

{ $grouptest = 'gm.groupid IN (' . implode(',', $groups) . ')'; }

else

{ $grouptest = 'gm.groupid = ' . $groups; }

$grouptest = 'ra.userid IN (SELECT userid FROM ' .
$CFG->prefix . 'groups_members gm WHERE ' . $grouptest . ')';

if ($useviewallgroups)

{ $viewallgroupsusers = get_users_by_capability($context, 'moodle/site:accessallgroups', 'u.id, u.id', '', '', '', '', $exceptions); $wherecond['groups'] = '('. $grouptest . ' OR ra.userid IN (' . implode(',', array_keys($viewallgroupsusers)) . '))'; }

else

{ $wherecond['groups'] = '(' . $grouptest .')'; }

}

if we change ra.userid to u.id in the code above, it will work. But I am not sure whether the changes will affect something else, so I report this bug and let the author of this file fix it.

once it is fixed, please inform us and I can upload the fixed file to solve our problems.

Thanks
Ye