Mysql/Java根據出生日期計算年齡

Mysql 根據出生日期計算年齡
1.DATEDIFF()計算天數差，一年365天5小時48分46秒（365.2422天），FLOOR()向下取整
SELECT name,birth,FLOOR(DATEDIFF(CURDATE(),birth)/365.2422) AS age FROM sys_user
  
2.DATEDIFF()計算天數差，FROM_DAYS()將天數轉換爲日期格式
SELECT name,birth,YEAR(FROM_DAYS(DATEDIFF(CURDATE(),birth))) AS age FROM sys_user
  
3.看着稍微複雜點，仔細看就是當前日期年相差，月份比較
SELECT name,birth,
(YEAR(CURDATE())-YEAR(birth)-1) + (DATE_FORMAT(birth,'%m%d') <= DATE_FORMAT(CURDATE(),'%m%d')) AS age
FROM sys_user

比較年比較月份，可以得到幾週歲又幾個月
SELECT name,birth,YEAR(CURDATE())-YEAR(birth) AS age,
(MONTH(NOW())-MONTH(birth)) AS month FROM sys_user
  
4.TIMESTAMPDIFF()函數，這個是目前最精簡的
SELECT name,birth,TIMESTAMPDIFF(YEAR,birth,CURDATE()) AS age FROM sys_user

Java 根據出生日期計算年齡
/**
 * 根據出生年月計算年齡
 * @param birth
 * @return age
 */
public static String getAgeByBirth(String birth){
   if ("".equals(birth.trim()) || birth.trim() == null) {
      return null;
   }
   //此處調用了獲取當前日期，以yyyy-MM-dd格式返回的日期字符串方法
   String nowDate = DateUtils.getDate();
   int age = Integer.parseInt(nowDate.substring(0, 4))- Integer.parseInt(birth.substring(0,4));
   return Integer.toString(age);
}