MySQL实现出生年月转年龄

描述及实现

表达函数：

$f ( b i r t h d a y ) = { n o w D a t e − b i r t h d a y ( 岁 ) n o w D a t e − b i r t h d a y ≥ 1 年 n o w D a t e − b i r t h d a y ( 月 ) 1 年 > n o w D a t e − b i r t h d a y ≥ 1 月 n o w D a t e − b i r t h d a y ( 天 ) 1 月 > n o w D a t e − b i r t h d a y ≥ 0 天 f(birthday)=\begin{cases} nowDate-birthday (岁) & nowDate-birthday ≥ 1年 \\ nowDate-birthday (月) & 1年 > nowDate-birthday ≥ 1月 \\ nowDate-birthday (天) & 1月 >nowDate-birthday ≥ 0天 \\ \end{cases}$ f(birthday)=⎩ ⎨ ⎧nowDate−birthday(岁)nowDate−birthday(月)nowDate−birthday(天)nowDate−birthday≥1年1年>nowDate−birthday≥1月1月>nowDate−birthday≥0天

nowDate：现在日期
birthday：出生年月日

SQL代码：

sql 复制代码

select
	case
		when TIMESTAMPDIFF(year,'birthday',CURDATE()) != 0 
			then CONCAT(TIMESTAMPDIFF(year, 'birthday', CURDATE()), '岁')
		when TIMESTAMPDIFF(month,'birthday',CURDATE()) != 12 * TIMESTAMPDIFF(year,'birthday',CURDATE()) 
			then CONCAT(TIMESTAMPDIFF(month, 'birthday', CURDATE())-12 * TIMESTAMPDIFF(year, 'birthday', CURDATE()), '月')
		else CONCAT(ABS(TIMESTAMPDIFF(day, 'birthday', CURDATE())), '天')
	end as age,
from
	dual;

实践及效果

示例代码：

sql 复制代码

select
	CURDATE() as currentDate,
	date_format('2023-1-14','%Y-%m-%d') as useYear, 
	case
		when TIMESTAMPDIFF(year,'2023-1-14',CURDATE()) != 0 
			then CONCAT(TIMESTAMPDIFF(year, '2023-1-14', CURDATE()), '岁')
		when TIMESTAMPDIFF(month, '2023-1-14', CURDATE()) != 12*TIMESTAMPDIFF(year, '2023-1-14', CURDATE()) 
			then CONCAT(TIMESTAMPDIFF(month, '2023-1-14', CURDATE())-12*TIMESTAMPDIFF(year, '2023-1-14', CURDATE()), '月')
		else CONCAT(ABS(TIMESTAMPDIFF(day, '2023-1-14', CURDATE())), '天')
	end as diffYear,
	date_format('2023-12-14','%Y-%m-%d') as useMonth, 
	case
		when TIMESTAMPDIFF(year ,'2023-12-14',CURDATE()) != 0 
			then CONCAT(TIMESTAMPDIFF(year, '2023-12-14', CURDATE()), '岁')
		when TIMESTAMPDIFF(month, '2023-12-14', CURDATE()) != 12*TIMESTAMPDIFF(year, '2023-12-14', CURDATE()) 
			then CONCAT(TIMESTAMPDIFF(month, '2023-12-14', CURDATE())-12*TIMESTAMPDIFF(year, '2023-12-14', CURDATE()), '月')
		else CONCAT(ABS(TIMESTAMPDIFF(day, '2023-12-14', CURDATE())), '天')
	end as diffMonth,
	date_format('2024-1-14','%Y-%m-%d') as useDay, 
	case
		when TIMESTAMPDIFF(year,'2024-1-14',CURDATE()) != 0 
			then CONCAT(TIMESTAMPDIFF(year, '2024-1-14', CURDATE()), '岁')
		when TIMESTAMPDIFF(month, '2024-1-14', CURDATE()) != 12*TIMESTAMPDIFF(year, '2024-1-14', CURDATE()) 
			then CONCAT(TIMESTAMPDIFF(month, '2024-1-14', CURDATE())-12*TIMESTAMPDIFF(year, '2024-1-14', CURDATE()), '月')
		else CONCAT(ABS(TIMESTAMPDIFF(day, '2024-1-14', CURDATE())), '天')
	end as diffDay
from
	dual;

示例效果：

使用总结

对于涉及到人的年龄表来说，由于年龄会随着时间变化而变化，一般不合适直接存储年龄字段。所以就需要通过存储的出生年月日，进行动态计算。