mysql
mysql> desc card_info;
+-------------+-----------+------+-----+-------------------+-------+
| field | type | null | key | default | extra |
+-------------+-----------+------+-----+-------------------+-------+
| card_number | char(20) | no | pri | | |
| hit_time | int(11) | no | | 0 | |
| modify_time | timestamp | no | | current_timestamp | |
+-------------+-----------+------+-----+-------------------+-------+
card_number做insert条件时，值需要加单引号；
做update条件时，一个长度为15的值不加单引号才能实现，一个长度为19的值无论加不加单引号都无法实现更新