mysql按天，小时，半小时，N分钟，分钟进行数据分组统计

mysql不同时间粒度下的分组统计

我们在做项目或者数据分析时，经常遇到这样的需求：统计不同时间粒度下的数据分布情况，例如，每一天中每个小时网站的访问量，某路口每半个小时通过的车辆数量等。对于此类的问题，一个sql简单的查询就能实现，故特此记录下，方便以后使用。
在MySQL中，我的表为：track
数据结构如下所示：

按天统计

SELECT DATE(TimeStart) AS date, COUNT(*) AS num
FROM track
WHERE Flag = 0 AND Duration >= 300 
GROUP BY date
ORDER BY date;

按小时统计

SELECT DATE_FORMAT(TimeStart, '%Y-%m-%d %H:00:00') AS time, COUNT(*) AS num
FROM track
WHERE Flag = 0 AND Duration >= 300
GROUP BY time
ORDER BY time;

结果如下：

按半小时统计

SELECT time, COUNT( * ) AS num 
FROM
	(
	SELECT Duration,
		DATE_FORMAT(
			concat( date( TimeStart ), ' ', HOUR ( TimeStart ), ':', floor( MINUTE ( TimeStart ) / 30 ) * 30 ),
			'%Y-%m-%d %H:%i' 
		) AS time 
	FROM tarck
	WHERE Flag = 0  AND Duration >= 300 
	) a 
GROUP BY DATE_FORMAT( time, '%Y-%m-%d %H:%i' ) 
ORDER BY time;

结果如下：

按N分钟统计

将上面的SQL语句稍微修改下，就可以实现按任意N分钟为时间片的分组统计，如按10分钟统计，先上代码：

SELECT time, COUNT( * ) AS num 
FROM
	(
	SELECT Duration,
		DATE_FORMAT(
			concat( date( TimeStart ), ' ', HOUR ( TimeStart ), ':', floor( MINUTE ( TimeStart ) / 10 ) * 10 ),
			'%Y-%m-%d %H:%i' 
		) AS time 
	FROM tarck
	WHERE Flag = 0  AND Duration >= 300 
	) a 
GROUP BY DATE_FORMAT( time, '%Y-%m-%d %H:%i' ) 
ORDER BY time;

基本思路：
将datetime类型的时间转化为相应时间片的时间，例如将‘2017-03-01 01:08:19’ 转化为‘2017-03-01 01:00:00’，然后group by即可。

按分钟统计

将按小时统计的SQL语句稍微修改下，就可以实现按分钟统计

SELECT DATE_FORMAT(TimeStart, '%Y-%m-%d %H:%i:00') AS time, COUNT(*) AS num
FROM track 
WHERE Flag = 0 AND Duration >= 300
GROUP BY time
ORDER BY time;

DATE_FORMAT功能强大，可以根据format字符串格式化date值，参考下面链接
http://www.w3school.com.cn/sql/func_date_format.asp
参考博客：

1. https://blog.youkuaiyun.com/kaka_buka/article/details/52614643
2. https://blog.youkuaiyun.com/Beingccccc/article/details/78685490