SELECT * FROM persons
WHERE datediff(date_add(birthday, INTERVAL (YEAR(curdate()) - YEAR(birthday)) YEAR), curdate()) BETWEEN 1 AND 30
OR datediff(date_add(birthday, INTERVAL (YEAR(curdate()) - YEAR(birthday) + 1) YEAR), curdate()) BETWEEN 1 AND 30;

where o3cm9_community_fields_values.field_id') . ' = '.  $fieldid['birthday'] .' AND o3cm9_community_fields_values.user_id') .' IN ('. $ids .')').