如何按日期按日期分組日期類型時間戳

Question

數據庫是mysql。表如此：

Create table Persons (_id int8 primary key, name varchar, birthday long); 

生日是生日的時間戳。

，所以我想選擇按日期組，這意味着該結果應該是一個創紀錄的一天

select sum(_id) from Persons group by .... 

誰能幫我的數據嗎？

Answer 1

也許是：

select sum(_id) from Persons group by DATE_FORMAT(FROM_UNIXTIME(birthday), '%d-%m-%Y') 

Answer 2

嘗試這種方式，

select sum(_id) FROM Persons GROUP BY DATE_FORMAT(birthday, '%Y%m%d') 

Answer 3

select sum(_id) from Persons group by date_format(birthday,'%y-%m-%d')