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I want to do the following: Find all articles with where Time.now is between article.due_date and article.due_date - 8.hours. I'm having a lot of trouble trying to get it right. Any help would be much appreciated.

Thanks!

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What is it that you are having problems with? – Jimmy Stenke Mar 7 '11 at 18:23
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1 Answer

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Who said that algebra was worthless?

The two conditions you stated in your question.

T <= DUE
T >= DUE - 8h

Are the same as these two conditions.

DUE >= T
DUE <= T + 8h

You can apply now apply this to a query and/or scope without having to do datetime gymnastics in your database.

named_scope :near_due, lambda {{ :conditions => ["due_date >= ? AND due_date <= ?", Time.now, Time.now + 8.hours] }}
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Ha. I just solved this myself. Had to relookup the rules for inequalities. Probably don't need the lambda unless we're passing the hours, which may indeed be a good idea. Have an accepted answer for your work though :) – Dave G Mar 7 '11 at 19:20
You definitely need the lambda, otherwise Time.now will only be evaluated the first time your model is cached. – jdl Mar 7 '11 at 19:25
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