Just to give another perspective... Do you really need to save the sum? Could it be calculated whenever you need it? If you save the sum you need to be confident that nothing will cause your data to get out of sync, such as some update to 'test' that does not update the sum. If you decide you do want to save the sum, could the database management system handle it for you? E.g. in PostgreSQL you can define triggers - in this case a trigger could update the sum for you no matter how 'test' and 'test2' are updated. You'd then have much greater faith in the reliability of each sum.
On Jan 16, 11:19 pm, Herman <[email protected]> wrote: > Basically what I'm trying to do is get the sum of 2 columns and save > those results in another. I guess I'm looking to do something like > this: > a = Product.find(:all) > b = Product.sum("test + test2", :group => "id") > a.test3 = b > a.save > > Obviously that doesn't work, but I'm trying to achieve something like > that. Any suggestions? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
