mysql 建立日期列之timestamp

mysql 有很多日期格式

這裡僅說明timestamp的應用

mysql> create table t1(id int,b timestamp default current_timestamp);

query ok, 0 rows affected (0.19 sec)
mysql> show create table t1\g
*************************** 1. row ***************************
table: t1
create table: create table `t1` (
`id` int(11) default null,
`b` timestamp not null default current_timestamp
) engine=innodb default charset=utf8
1 row in set (0.00 sec)
mysql> insert into t1(id) values(1);
query ok, 1 row affected (0.02 sec)
mysql> insert into t1(id) values(2);
query ok, 1 row affected (0.02 sec)
mysql> select * from t1;
+------+---------------------+
| id | b |
+------+---------------------+
| 1 | 2013-05-20 06:44:07 |
| 2 | 2013-05-20 06:44:08 |
+------+---------------------+
2 rows in set (0.00 sec)

mysql> create table t2(id int,b timestamp default current_timestamp on update current_timestamp)engine=innodb;

query ok, 0 rows affected (0.19 sec)
mysql> show create table t2\g
*************************** 1. row ***************************
table: t2
create table: create table `t2` (
`id` int(11) default null,
`b` timestamp not null default current_timestamp on update current_timestamp
) engine=innodb default charset=utf8
1 row in set (0.00 sec)
mysql> insert into t2(id) values(1);
query ok, 1 row affected (0.02 sec)
mysql> insert into t2(id) values(2);
query ok, 1 row affected (0.02 sec)
mysql> select * from t2;
+------+---------------------+
| id | b |
+------+---------------------+
| 1 | 2013-05-20 06:46:39 |
| 2 | 2013-05-20 06:46:43 |
+------+---------------------+
2 rows in set (0.00 sec)
mysql> update t2 set id=2 where id=1;
query ok, 1 row affected (0.02 sec)
rows matched: 1 changed: 1 warnings: 0
mysql> select * from t2;
+------+---------------------+
| id | b |
+------+---------------------+
| 2 | 2013-05-20 06:47:15 |
| 2 | 2013-05-20 06:46:43 |
+------+---------------------+
2 rows in set (0.00 sec)
mysql> update t2 set id=3 where b='2013-05-20 06:47:15';
query ok, 1 row affected (0.02 sec)
rows matched: 1 changed: 1 warnings: 0
mysql> select * from t2;
+------+---------------------+
| id | b |
+------+---------------------+
| 3 | 2013-05-20 06:47:59 |
| 2 | 2013-05-20 06:46:43 |
+------+---------------------+
2 rows in set (0.00 sec)
mysql> update t2 set id=3 where id=3;
query ok, 0 rows affected (0.00 sec)
rows matched: 1 changed: 0 warnings: 0
mysql> select * from t2;
+------+---------------------+
| id | b |
+------+---------------------+
| 3 | 2013-05-20 06:47:59 |
| 2 | 2013-05-20 06:46:43 |
+------+---------------------+
2 rows in set (0.00 sec)

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