Rails - Jul 2006 - Sorting by an attribute on a associated table

So, I have a User has_many :profiles. The most recently dated profile is 
considered the current one. I need to sort these users by name, but the 
name attribute is a member of the associated table.

Is there any easy way to do this other than with some ugly find_by_sql?

Maybe a more general question - is there a common solution to sorting in 
Ruby?

-- 
Posted via http://www.ruby-forum.com/.

What about using acts_as_list, :order => :date_added (or whatever you  
call that column)? Then you could say

def profile
   profilies.first
end

.... I think :)

On Jul 1, 2006, at 9:17 AM, Bryan Duxbury wrote:
> So, I have a User has_many :profiles. The most recently dated  
> profile is
> considered the current one. I need to sort these users by name, but  
> the
> name attribute is a member of the associated table.
>
> Is there any easy way to do this other than with some ugly  
> find_by_sql?
>
> Maybe a more general question - is there a common solution to  
> sorting in
> Ruby?
>
> -- 
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Something like

@user.profiles.find(:all, :order => "name DESC")

Bryan Duxbury wrote:
> So, I have a User has_many :profiles. The most recently dated profile is 
> considered the current one. I need to sort these users by name, but the 
> name attribute is a member of the associated table.
> 
> Is there any easy way to do this other than with some ugly find_by_sql?
> 
> Maybe a more general question - is there a common solution to sorting in 
> Ruby?

-- 
Posted via http://www.ruby-forum.com/.

Perhaps I was unclear. I have no trouble sorting the profiles 
themselves.

What I want to do is sort the USERS by an attribute on their most recent 
profile. Something along the lines of:

@users = User.find(:all, :order => |user| {user.profile.firstname})

Of course I totally made that syntax up.

-- 
Posted via http://www.ruby-forum.com/.

Bryan Duxbury wrote:
> Perhaps I was unclear. I have no trouble sorting the profiles 
> themselves.
>
> What I want to do is sort the USERS by an attribute on their most recent 
> profile. Something along the lines of:
>
> @users = User.find(:all, :order => |user| {user.profile.firstname})
>
> Of course I totally made that syntax up.
>
>   
I don''t know how to do this in SQL but I can give you some ruby that 
will get you going.

@users = User.find(:all)
@users.sort_by {|user| user.profile.firstname}

This will be really slow compared to a pure SQL sort so I would still 
look for a way to do that.

Matthew Margolis
blog.mattmargolis.net

Matthew Margolis wrote:
> Bryan Duxbury wrote:
>>   
> I don''t know how to do this in SQL but I can give you some ruby
that
> will get you going.
> 
> @users = User.find(:all)
> @users.sort_by {|user| user.profile.firstname}
> 
> This will be really slow compared to a pure SQL sort so I would still
> look for a way to do that.
> 
> Matthew Margolis
> blog.mattmargolis.net
Awesome, that''s exactly what I was looking for. Thanks!

-- 
Posted via http://www.ruby-forum.com/.

Matthew Margolis wrote:
> Bryan Duxbury wrote:
>> Perhaps I was unclear. I have no trouble sorting the profiles
themselves.
>>
>> What I want to do is sort the USERS by an attribute on their most 
>> recent profile. Something along the lines of:
>>
>> @users = User.find(:all, :order => |user| {user.profile.firstname})
>>
>> Of course I totally made that syntax up.
>>   
> I don''t know how to do this in SQL but I can give you some ruby
that
> will get you going.
> 
> @users = User.find(:all)
> @users.sort_by {|user| user.profile.firstname}
> 
> This will be really slow compared to a pure SQL sort so I would still 
> look for a way to do that.
> 
Something like this should do the trick in pure SQL.

@users = User.find(:all, :include => :profile, :order => 
"profiles.firstname ASC")

Or just do a join if you don''t want to instantiate all the profiles.

hth

-- 
R.Livsey
http://livsey.org