发生了一个数据库错误

Error Number: 1064

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'and rht< order by listorder asc' at line 1

select * from en_category where class="" and lft> and rht< order by listorder asc

Filename: /home/nanzhoutnjawntznheoiu/wwwroot/en/models/model_category.php

Line Number: 116