Count uniques ?

[Adriano Lul]

I need to know how I use the count function to have a sum of days
ie: I have several transactions in several days like hmmm Tasks
Task -> id, price, day , description

so in every day I did some tasks
I sum them with the Task.sumprice)
but I want to do an automatized way to have an average description (sum
/ days )
how can I do it ?
ps: day is datetime ...

 

[Roger Pack]

You can substract datetimes to get the difference between them in seconds.
Time.now - Time.now
Use that to average?