了解每天注册的人数

Question

在mySQL中，我要做的是查询我的表并找出每天注册的人数。换句话说，我希望能够在一个月内产生以下输出：

1 January: 10 registrations
2 January: 150 registrations
3 January: 50  registrations

select created, regID
from registrations  

日期在DB：2012-11-01 00:00:00

中采用以下格式

Answer 1

要获取1月份每天的注册计数，请使用此select：

select daymonth(registration_date), count(*)
from registrations
where registration_date >= '01/01/2012' and registration_date <= '01/31/2012'
group by daymonth(registration_date)

Answer 2

您通常使用分组运算符：

SELECT COUNT(*) AS registrations, DATE(created) AS created_date GROUP BY created_date

如果created已经是DATE列，则不需要转换。

Answer 3

试试这个：

SELECT created, count(regID) FROM registrations GROUP BY created ORDER BY created ASC

Answer 4

SELECT   DATE(DATE_REGISTERED) DATE, COUNT(*) totalRegistered
FROM     tableName
GROUP BY DATE