Find position in active record object

Question

I have a league table that i create with:

 QuizuserAnswer.all(:include =>:user, :select => 'user_id, SUM(answer) AS points', :group =>'user_id', :order=>'points DESC'

This returns an object like this:

 => [#<QuizuserAnswer user_id: 340>, #<QuizuserAnswer user_id: 348>]

Now i want to find the league table position of one specific user. Is there a clean way? or do i have to loop through al columns?

If you are using MySQL then follow this link http://stackoverflow.com/q/3126972/1460496 — techvineet, Sep 03 '13 at 12:58
I'm using mysql. With position i meant the row number, because they reflect the position of a user in the league table — flyte321, Sep 03 '13 at 13:07

score 13 · Accepted Answer · answered Sep 03 '13 at 12:55

13

From a very little i got your question i think you want something like following

answers = QuizuserAnswer.all(:include =>:user, :select => 'user_id, SUM(answer) AS points', :group =>'user_id', :order=>'points DESC')
user_id = 348
answers.map(&:user_id).index(user_id) #This will return 1

i.e It will return the position of the answer given by the user among the answer's list

answered Sep 03 '13 at 12:55

Salil

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@flyte321 :- Cheer's, remember one thing it will return `nil` if `user_id` is not present in `answers` – Salil Sep 03 '13 at 13:08
This actually solved my issue of trying to generate a "next" button in an action record collection with a scope – dannio Jan 13 '15 at 07:52

Find position in active record object

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