最近要经常用到mysql的日期相关函数，但以前用的少，索性总结下
1 DATE_FORMAT(date,format)
published_at字段以datetime类型存储
SELECT title,DATE_FORMAT(published_at,'%Y-%m-%d') FROM blog_note WHERE DATE_FORMAT(published_at,'%Y-%m')='2023-09'
2 STR_TO_DATE(str,format)
SELECT title,STR_TO_DATE(published_at,'%Y-%m-%d') FROM blog_note
3 UNIX_TIMESTAMP(date)
SELECT title,UNIX_TIMESTAMP(published_at) ,published_at FROM blog_note
4 FROM_UNIXTIME(timestamp,format)
SELECT title,FROM_UNIXTIME(UNIX_TIMESTAMP(published_at) ,'%Y-%m-%d %H:%i:%s'),published_at FROM blog_note
5 CURRENT_DATE()
SELECT CURRENT_DATE(),DATE_ADD(CURRENT_DATE(),INTERVAL 1 DAY) ,DATE_ADD(CURRENT_DATE(),INTERVAL -1 DAY) ,DATE_SUB(CURRENT_DATE(),INTERVAL -1 DAY)
SELECT DATE_ADD(CURRENT_DATE(),INTERVAL 1 MONTH) ,DATE_ADD('2023-12-01',INTERVAL 1 DAY) ,DATE_ADD(NOW(),INTERVAL '1::20:30' HOUR_SECOND),DATE_ADD(NOW(),INTERVAL '1::20' YEAR_MONTH)
