-- 今天
SELECT DATE_FORMAT(NOW(),'%Y-%m-%d 00:00:00') AS '今天开始';
SELECT DATE_FORMAT(NOW(),'%Y-%m-%d 23:59:59') AS '今天结束';

-- 昨天
SELECT DATE_FORMAT( DATE_SUB(CURDATE(), INTERVAL 1 DAY), '%Y-%m-%d 00:00:00') AS '昨天开始';
SELECT DATE_FORMAT( DATE_SUB(CURDATE(), INTERVAL 1 DAY), '%Y-%m-%d 23:59:59') AS '昨天结束';

-- 上周
SELECT DATE_FORMAT( DATE_SUB( DATE_SUB(CURDATE(), INTERVAL WEEKDAY(CURDATE()) DAY), INTERVAL 1 WEEK), '%Y-%m-%d 00:00:00') AS '上周一';
SELECT DATE_FORMAT( SUBDATE(CURDATE(), WEEKDAY(CURDATE()) + 1), '%Y-%m-%d 23:59:59') AS '上周末';

-- 本周
SELECT DATE_FORMAT( SUBDATE(CURDATE(),DATE_FORMAT(CURDATE(),'%w')-1), '%Y-%m-%d 00:00:00') AS '本周一';
SELECT DATE_FORMAT( SUBDATE(CURDATE(),DATE_FORMAT(CURDATE(),'%w')-7), '%Y-%m-%d 23:59:59') AS '本周末';
-- 上面的本周算法会有问题,因为mysql是按照周日为一周第一天,如果当前是周日的话,会把时间定为到下一周.
SELECT DATE_FORMAT( DATE_SUB(CURDATE(), INTERVAL WEEKDAY(CURDATE()) DAY), '%Y-%m-%d 00:00:00') AS '本周一';
SELECT DATE_FORMAT( DATE_ADD(SUBDATE(CURDATE(), WEEKDAY(CURDATE())), INTERVAL 6 DAY), '%Y-%m-%d 23:59:59') AS '本周末';

-- 上月
SELECT DATE_FORMAT( DATE_SUB(CURDATE(), INTERVAL 1 MONTH), '%Y-%m-01 00:00:00') AS '上月初';
SELECT DATE_FORMAT( LAST_DAY(DATE_SUB(CURDATE(), INTERVAL 1 MONTH)), '%Y-%m-%d 23:59:59') AS '上月末';

-- 本月
SELECT DATE_FORMAT( CURDATE(), '%Y-%m-01 00:00:00') AS '本月初';
SELECT DATE_FORMAT( LAST_DAY(CURDATE()), '%Y-%m-%d 23:59:59') AS '本月末';