MySQL中根据出生日期计算年龄两种方法

mysql> create table student(                                                                            
    ->     sid int primary key comment '学生号',                                                        
    ->     sname varchar(20) comment'姓名',                                                             
    ->     birth DATE comment '生日'                                                                    
    -> );                                                                                               
Query OK, 0 rows affected (0.01 sec)

mysql> insert into student values (100,'张三','1999-12-12');                                            
Query OK, 1 row affected (0.00 sec)                                                                     
mysql> insert into student values (101,'李四','1996-8-15');                                             
Query OK, 1 row affected (0.01 sec)

mysql> select *  from student;

-- 获取当前日期和年龄
SELECT CURDATE();

SELECT YEAR('2000-01-01');

SELECT YEAR('2022-01-01') - YEAR('2000-01-01');

-- 计算出生日期
SET @current_year = YEAR(CURDATE());
SET @age = 30;
SET @birth_year = @current_year - @age;

SET @birth_date = CONCAT(@birth_year, '-01-01');

-- 使用MySQL函数实现计算
SET @current_date = CURDATE();
SET @birth_date = DATE_SUB(@current_date, INTERVAL @age YEAR);