thanks colin and rob, that's approximately what I have so far,
I was hoping a solution to do it in one request :-/
On Sep 23, 3:08 pm, Rob Biedenharn <r...@agileconsultingllc.com>
wrote:
> On Sep 23, 2009, at 7:49 AM, mickeyben wrote:
>
>
>
>
>
> > On Sep 23, 2:38 pm, Colin Law <clan...@googlemail.com> wrote:
> >> 2009/9/23 Bensoussan Michael <pad...@gmail.com>:
> >>> Hi,
> >>> How would you get an SQL element, the next one and the previous one,
> >>> but the definition of a next/previous element is not dependant
> >>> only of
> >>> his id but also of a status,
> >>> example :
>
> >>> id status
> >>> 1 true
> >>> 2 false
> >>> 3 true
>
> >>> Here the next element of 1 is 3
>
> >> If I understand correctly you can specify an order in the find call
> >> that provides the records in whatever order you want.
>
> >> Note also that if you do not specify an order then there is no
> >> guarantee in what order they will appear. They will not necessarily
> >> be in id order.
>
> >> Colin
>
> > yes but that doesnt resolve my problem (I think), I don't want to
> > select all the database, otherwise I just need to filter by status an
> > order by id, I just want this 3 results :-/
>
> This might help. These are some class methods to do something similar.
>
> def self.prior_to id
> find(:first, :conditions => ["#{primary_key} < ?", id], :order =>
> "#{primary_key} DESC") ||
> find(:first, :conditions => ["#{primary_key} >= ?", id], :order
> => "#{primary_key}")
> end
>
> def self.next_after id
> find(:first, :conditions => ["#{primary_key} > ?", id], :order =>
> "#{primary_key}") ||
> find(:first, :conditions => ["#{primary_key} <= ?", id], :order
> => "#{primary_key} DESC")
> end
>
> You'd want to adjust the conditions to also look at status and
> probably take a model instance rather than an id. Maybe even a list of
> the attributes that must be matched (just :status in your example).
>
> -Rob
>
> Rob Biedenharn http://agileconsultingllc.com
> r...@agileconsultingllc.com
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