计算两次之间的分钟数，然后除以记录量

Question

How can we calculate the amount of minutes between 9 and 11 of all the records togther (colum is generated). I also want to know how I can devide the output of that by the amount of records there are.

select  address,
        min(from_unixtime(time)) "Aankomsttijd",
        max(from_unixtime(time)) "Eindtijd",
        TIMESTAMPDIFF(MINUTE, min(from_unixtime(time)), max(from_unixtime(time))) "Minuten"
from    sensordata1
Where   from_unixTime(sensordata1.time) BETWEEN '2017/04/04' AND '2017/04/05' AND
        from_unixTime(sensordata1.time, '%H') BETWEEN 9 AND 11
group by address  
having Minuten > 2 AND Minuten < 1400

Output

Normal database as you can see "Minuten is not a real column"

What I want to get is all the minutes together as 1 amount and I want that to devide by the amount of records they calculated the minutes together.

Answer 1

You can use that query you wrote as source for the calculation you want, like

select  sum(Minuten) total_minuten,
        count(*) records,
        sum(Minuten) / count(*) average_minuten
from    (
            select  address,
                    min(from_unixtime(time)) "Aankomsttijd",
                    max(from_unixtime(time)) "Eindtijd",
                    TIMESTAMPDIFF(
                      MINUTE,
                      min(from_unixtime(time)),
                      max(from_unixtime(time))
                    ) "Minuten"
            from    sensordata1
            Where   from_unixTime(sensordata1.time) BETWEEN '2017/04/04' AND '2017/04/05' AND
                    from_unixTime(sensordata1.time, '%H') BETWEEN 9 AND 11
            group by address  
            having Minuten > 2 AND Minuten < 1400
        ) t1