获取上月初

SELECT DATE_FORMAT( DATE_SUB(str_to_date('2022-12-01', '%Y-%m-%d'), INTERVAL 1 MONTH), '%Y-%m-01');

获取上月末

SELECT DATE_FORMAT( LAST_DAY(DATE_SUB(str_to_date('2022-12-01', '%Y-%m-%d'), INTERVAL 1 MONTH)), '%Y-%m-%d');
select str_to_date('2022-12-01', '%Y-%m-%d')

SELECT DATE_FORMAT(date_sub(str_to_date('20221201', '%Y%m%d'), INTERVAL 4 day),'%Y%m%d')