## to_days，unix_timestamp
### 说明
| 函数 | 说明 |
| --- | --- |
| to_days(date) | 返回公元0年到date的天数 |
| unix_timestamp(date)| 将日期转换成时间戳 |
### 例子：查询宝宝出生天数
```sql
SELECT
id,
baby_name,
baby_birthday,
(to_days(now()) - to_days(baby_birthday)) AS baby_dayage,
(unix_timestamp(now()) - unix_timestamp(baby_birthday))/86400 as baby_dayage1
FROM
baby;
```
