MySQL 8 教程

示例：使用日期和时间函数

下面是一些使用日期和时间函数的实际示例：

-- 获取当前日期和时间
SELECT NOW() AS current_datetime, CURDATE() AS current_date, CURTIME() AS current_time;

-- 格式化日期
SELECT DATE_FORMAT(NOW(), '%Y-%m-%d %H:%i:%s') AS formatted_datetime;
SELECT DATE_FORMAT(NOW(), '%Y年%m月%d日 %H时%i分%s秒') AS chinese_format;

-- 计算日期差
SELECT DATEDIFF('2023-12-31', '2023-10-15') AS days_until_new_year;

-- 添加和减去日期时间
SELECT DATE_ADD(NOW(), INTERVAL 7 DAY) AS next_week;
SELECT DATE_SUB(NOW(), INTERVAL 1 MONTH) AS last_month;
SELECT ADDTIME(NOW(), '01:30:00') AS one_and_half_hour_later;

-- 提取日期部分
SELECT YEAR(NOW()) AS year, MONTH(NOW()) AS month, DAY(NOW()) AS day;
SELECT HOUR(NOW()) AS hour, MINUTE(NOW()) AS minute, SECOND(NOW()) AS second;

-- 使用EXTRACT函数
SELECT EXTRACT(YEAR FROM NOW()) AS year, EXTRACT(QUARTER FROM NOW()) AS quarter;

-- UNIX时间戳转换
SELECT UNIX_TIMESTAMP(NOW()) AS current_timestamp;
SELECT FROM_UNIXTIME(1697356225) AS datetime_from_timestamp;

-- 字符串转换为日期
SELECT STR_TO_DATE('2023-10-15', '%Y-%m-%d') AS date_from_string;
SELECT STR_TO_DATE('2023年10月15日', '%Y年%m月%d日') AS chinese_date_from_string;