Coding Tree

时间日期类型

类型	名称	存储字节数	格式	表示范围	初始值
Date	日期类型	3字节	`YYYY-mm-dd`	`1000-01-01~9999-12-12`	`0000-00-00`
Time	时间类型	3字节	`HH:ii:ss`	`-838:59:59~838:59:59`
Datetime	日期时间类型	8字节	`YYYY-mm-dd HH:ii:ss`	`1000-01-01 00:00:00 ~ 9999-12-12 23:59:59`	`0000-00-00 00:00:00`
Timestamp	时间戳类型		`YYYY-mm-dd HH:ii:ss`	表示从格林威治时间开始
Year	年类型	1字节	`0~99`/ 四位数具体年	`1900-2155`

特殊性：

1、year 插入2位数，有如下规则

69以下为20+
70以上为19+

2、timestamp可以自动更新

sql

timestamp null default current_timestamp on update current_timestamp

3、time可以存放小时超过24的值

4、时间time,可以使用简单的日期 + 空格 + 数字，会自动转换该数字成天数*24 + 后面的时间

示例

sql

create table my_date(
    date_field date,
    time_field time,
    datetime_field datetime,
    timestamp_field timestamp,
    year_field year
);

mysql> desc my_date;
+-----------------+-----------+------+-----+---------+-------+
| Field           | Type      | Null | Key | Default | Extra |
+-----------------+-----------+------+-----+---------+-------+
| date_field      | date      | YES  |     | NULL    |       |
| time_field      | time      | YES  |     | NULL    |       |
| datetime_field  | datetime  | YES  |     | NULL    |       |
| timestamp_field | timestamp | YES  |     | NULL    |       |
| year_field      | year(4)   | YES  |     | NULL    |       |
+-----------------+-----------+------+-----+---------+-------+

-- 插入正常数据
insert into
my_date(date_field, time_field, datetime_field, timestamp_field, year_field)
values ('1970-01-01', '10:12:12', '1970-01-01 10:12:12', '1970-01-01 10:12:12', 1970);

mysql> select * from my_date;
+------------+------------+---------------------+---------------------+------------+
| date_field | time_field | datetime_field      | timestamp_field     | year_field |
+------------+------------+---------------------+---------------------+------------+
| 1970-01-01 | 10:12:12   | 1970-01-01 10:12:12 | 1970-01-01 10:12:12 |       1970 |
+------------+------------+---------------------+---------------------+------------+

-- 插入time小时数超过24
insert into
my_date(date_field, time_field, datetime_field, timestamp_field, year_field)
values ('1970-01-01', '512:12:12', '1970-01-01 10:12:12', '1970-01-01 10:12:12', 50);

mysql> select * from my_date;
+------------+------------+---------------------+---------------------+------------+
| date_field | time_field | datetime_field      | timestamp_field     | year_field |
+------------+------------+---------------------+---------------------+------------+
| 1970-01-01 | 10:12:12   | 1970-01-01 10:12:12 | 1970-01-01 10:12:12 |       1970 |
| 1970-01-01 | 512:12:12  | 1970-01-01 10:12:12 | 1970-01-01 10:12:12 |       2050 |
+------------+------------+---------------------+---------------------+------------+

-- time格式转换
insert into
my_date(date_field, time_field, datetime_field, timestamp_field, year_field)
values ('1970-01-01', '5 12:12:12', '1970-01-01 10:12:12', '1970-01-01 10:12:12', 50);

mysql> select * from my_date;
+------------+------------+---------------------+---------------------+------------+
| date_field | time_field | datetime_field      | timestamp_field     | year_field |
+------------+------------+---------------------+---------------------+------------+
| 1970-01-01 | 10:12:12   | 1970-01-01 10:12:12 | 1970-01-01 10:12:12 |       1970 |
| 1970-01-01 | 512:12:12  | 1970-01-01 10:12:12 | 1970-01-01 10:12:12 |       2050 |
| 1970-01-01 | 132:12:12  | 1970-01-01 10:12:12 | 1970-01-01 10:12:12 |       2050 |
+------------+------------+---------------------+---------------------+------------+

PHP中的时间转换函数

字符串转时间戳 strtotime
时间戳转字符串 date

通常使用int保存时间戳

时间日期类型 ​

时间日期类型