MySQL next / previous ids（任意排序顺序）

Here is my table:

这是我的表:

mysql> describe ps;
+-------+---------+------+-----+---------+----------------+
| Field | Type    | Null | Key | Default | Extra          |
+-------+---------+------+-----+---------+----------------+
| id    | int(11) | NO   | PRI | NULL    | auto_increment | 
| a     | text    | YES  |     | NULL    |                | 
| b     | text    | YES  |     | NULL    |                | 
| c     | text    | YES  |     | NULL    |                | 
+-------+---------+------+-----+---------+----------------+
4 rows in set (0.00 sec)
mysql> describe ps