table orders
+----+--------+------------+
|s.no| id | ordername |
+----+--------+------------+
| 1 | 34 | name |
+----+--------+------------+
| 2 | 35 | name |
+----+--------+------------+
| 3 | 36 | name |
+----+--------+------------+
| 4 | 37 | name |
+----+--------+------------+
| 5 | 38 | name |
+----+--------+------------+
编写自动生成序列号的查询，当我从 sql 中删除订单时，序列号在 serial_number 行中应为 1234567，我使用订单 ID 作为自动增量