注意i：注意大小写

timestamp\date–>string

SELECT now(),from_timestamp(now(),'yyyyMMdd');

string->timestamp

SELECT '20230710',to_timestamp('20230710','yyyyMMdd');

日期加减

select '20231201',from_timestamp(date_add(to_timestamp('20231201','yyyyMMdd'),1),'yyyyMMdd') as "D+1"

获取去年years\months\days

select now(),date_add(now(),interval -1 years) as "Y-1";