【原】MySQL时间戳timestamp比较

DROP TABLE IF EXISTS `t`;
CREATE TABLE `t` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `ts` timestamp ,
  PRIMARY KEY (`id`)
) ;

INSERT INTO `t` VALUES ('1', '2014-01-06 17:01:36');

-- DELETE FROM t WHERE ts < UNIX_TIMESTAMP(CONCAT(DATE_SUB(DATE(NOW()),INTERVAL -3 MONTH ),' ',CURTIME())) 
SELECT
    ts,
    UNIX_TIMESTAMP(ts) < UNIX_TIMESTAMP
        (
            CONCAT(
                DATE_SUB(DATE(NOW()), INTERVAL 3 MONTH),
                ' ',
                CURTIME()
            )
        ),
        (
            CONCAT(
                DATE_SUB(
                    DATE(NOW()),
                    INTERVAL 3 MONTH
                ),
                ' ',
                CURTIME()
            )
        ),
   UNIX_TIMESTAMP(ts) < UNIX_TIMESTAMP
        (
            CONCAT(
                DATE_SUB(DATE(NOW()), INTERVAL 1 MONTH),
                ' ',
                CURTIME()
            )
        ),
        (
            CONCAT(
                DATE_SUB(
                    DATE(NOW()),
                    INTERVAL 1 MONTH
                ),
                ' ',
                CURTIME()
            )
        )

    FROM
        t

 php 相关代码

date('Y-m-d H:i:s', strtotime('-3 month'));