获取当前系统时间并从中依次取出对应的年月日和时间和周

select year(now())  as year;
select month(now())  as month;
select day(now())  as day;
select time(now())  as time;
SELECT YEARWEEK(now()); --获取当前周
SELECT QUARTER('2022-12-01'); --获取当前季度