mysql 创建时间字段

alter table table1 add order_date datetime null;

mysql> select * from table1;
+----------+------------+-----+------------+
| name_new | transactor | pid | order_date |
+----------+------------+-----+------------+
| 1hahha   | 1xiaohong  |   1 | NULL       |
| 2hahha   | 2xiaohong  |   2 | NULL       |
| 3hahha   | 3xiaohong  |   3 | NULL       |
| 4hahha   | 4xiaohong  |   4 | NULL       |
| 3hahha   | bob        |   5 | NULL       |
| 3hahha   | lee        |   6 | NULL       |
+----------+------------+-----+------------+
6 rows in set (0.00 sec)