mysql 年月日和年月日时分秒转换

SELECT `lssq-register`.bu_bus_act_base_info 
# 将 xxxx-yy-dd HH:mm:ss 的时间转化为 xxxx-yy-dd 00:00:00 (例如 2021-05-13 13:23:53 更改为 2021-05-13 00:00:00)
effect_start_time = date(effect_start_time),
use_effect_start_time = date(use_effect_start_time),
# 将 xxxx-yy-dd HH:mm:ss 的时间转化为 xxxx-yy-dd 23:59:59 (例如 2021-05-13 13:23:53 更改为 2021-05-13 23:59:59)
# DATE_FORMAT 将 2021-05-13 13:23:53 转化为 2021-05-13,然后拼接 ‘ 23:59:59‘ 之后再通过 STR_TO_DATE 转化为 2021-05-13 23:59:59
effect_end_time = STR_TO_DATE(CONCAT(DATE_FORMAT(effect_end_time,‘%Y-%m-%d‘),‘ 23:59:59‘),‘%Y-%m-%d %H:%i:%s‘),
use_effect_end_time = STR_TO_DATE(CONCAT(DATE_FORMAT(use_effect_end_time,‘%Y-%m-%d‘),‘ 23:59:59‘),‘%Y-%m-%d %H:%i:%s‘);