On Jul 6, 2:35 pm, Yanni Mac <[email protected]> wrote:
> I figured it out right after I posted ;-) Always happens like that..
> Here is the solution (or one of them)
>
> @widgets = Widget.find(:all,:select=>"widgets.*,count(foos.id) as
> foos_count",:joins=>"LEFT JOIN foos ON widgets.id =
> foos.widget_id",:group=>"widgets.id",:having=>"foos_count=0")
>
I think that
Widget.find(:all,:select=>"widgets.*",:joins=>"LEFT OUTER JOIN foos ON
widgets.id =foos.widget_id ",
:conditions => "foos.id is NULL")
might be faster (since the database can infer from that that you want
widgets with no foos which is a bit less work than doing all the
counting and then filtering that.
Fred
>
> Yanni Mac wrote:
> > I have a widget model that has_many foos. I want to find a list of
> > widgets that have no foos. Can I do this with a "find" method? Right
> > now I am selecting all widgets and iterating through them to look at
> > .count. I know there is a better way to do this, but I haven't been
> > able to figure it out with a single SQL query. Any ideas?
>
> > Thanks!
>
> --
> Posted viahttp://www.ruby-forum.com/.
--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---
