select f_ca_id, f_ca_name from tbl_category and length(f_ca_id) = '6' order by f_sort desc, f_ca_id
1064 : You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'and length(f_ca_id) = '6' order by f_sort desc, f_ca_id' at line 1