获取当月第一天Oracle写法：trunc(add_months(last_day(sysdate), -1) + 1)MySQL写法：DATE_ADD(now(),interval -day(now())+1 day)将当前时间添加-1个月Oracle写法：add_months(sysdate,

获取当月第一天：DATE_ADD(curdate(),interval -day(curdate())+1 day))ADDDATE(NOW(), INTERVAL -#{start} MONTH)%Y-%m-%d %TOracle:(SYSDATE- STR_TO_DATE(b.CREATE_TM