I have an application where I can list Items and add tags to each Item. The models Items and Tags are associated like this:
class Item < ActiveRecord::Base
has_many :taggings
has_many :tags, :through => :taggings
end
class Tagging < ActiveRecord::Base
belongs_to :item
belongs_to :tag
end
class Tag < ActiveRecord::Base
has_many :taggings
has_many :items, :through => :taggings
end
So, this many-to-many relationship allows me to set n tags for each Item, and the same tag can be used several times.
I'd like to list all tags ordered by the number of items associated with this tag. More used tags, shows first. Less used, last.
How can I do that?
Regards.
Tag.joins(:taggings).select('tags.*, count(tag_id) as "tag_count"').group(:tag_id).order(' tag_count desc')
try it desc, asc and see the difference.
We need select, to have tag_count column, and we need tag_count column to apply order to it, rest all straight forward join and grouping.
Btw, why dont you try this out https://github.com/mbleigh/acts-as-taggable-on