# Count uniques?

**URL:** <https://www.ruby-forum.com/t/count-uniques/136051>\
**Category:** Ruby\
**Created:** [April 28, 2008, 1:53pm UTC](https://www.ruby-forum.com/t/count-uniques/136051 "2008-04-28T13:53:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![adrianod](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c2a13f/32.png) [@adrianod](https://www.ruby-forum.com/u/adrianod)\
**Post date:** [April 28, 2008, 1:53pm UTC](https://www.ruby-forum.com/t/count-uniques/136051/1 "2008-04-28T13:53:02Z")

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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.sum(:price)  
but I want to do an automatized way to have an average description (sum  
/ days )  
how can I do it ?  
ps: day is datetime …

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<div class="post-metadata">

**Author:** ![adrianod](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c2a13f/32.png) [@adrianod](https://www.ruby-forum.com/u/adrianod)\
**Post date:** [April 28, 2008, 6:22pm UTC](https://www.ruby-forum.com/t/count-uniques/136051/2 "2008-04-28T18:22:45Z")

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