计算每月表中的平均小时数

Question

I have a table named "loginhistory", and I need to calculate the most active hour of the month. How can i do it?

My table structure is: id, userId, date (datetime), ip.

I tried to do it in PHP but I did not succeed there either. I prefer the calculation to be done only in MySql.

I expect the output to be just the number of the most active hour.

Answer 1

It does not matter checking average number if needed to pick active hour.

Cause average = count / days and since days is the same for whole calculation (let's say 30 ) the greatest count will be active hour in list.

Just select by date range and group by hour and pick 1st one from descending sort:

SELECT 
  HOUR(date) AS hour,
  COUNT(id) AS logins,
  ( COUNT(id) / DAY(LAST_DAY('2019-01-01')) ) AS logins_avg
FROM loginhistory
WHERE 
  date >= '2019-01-01 00:00:00' AND date < '2019-02-01 00:00:00'
GROUP BY HOUR(date)
ORDER BY logins DESC LIMIT 1