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
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
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
