arel

Let's say we have the following: irb> Post.where(:hidden => true).to_sql => "SELECT `posts`.* FROM `posts` WHERE posts.hidden = 1" Could we somehow get an inverted SQL query out of it? What I am looking for, should probably look like this: irb> Post.where(:hidden => true).invert.to_sql => "SELECT `posts`.* FROM `posts` WHERE NOT (posts.hidden = 1)" With a different syntax, yes. Example: posts = Post.scoped.table # or Arel::Table.new("posts") posts.where(posts[:hidden].eq(true).not).to_sql # => SELECT FROM `posts` WHERE NOT ((`posts`.`hidden` = 1)) In rails 4 there is not suffix for this

I want to grab all the categories that contain purchaseable products . class Product < ActiveRecord::Base belongs_to :category scope :purchaseable, where(:available => true) end class Category < ActiveRecord::Base has_many :products scope :with_purchaseable_products, ????? end So, I'm trying to define :with_purchaseable_products . This works: scope :with_purchaseable_products, joins(:products).where("products.available is true").group(:id).having('count(products.id) > 0') But that's not very DRY. Is there any way to apply my :purchaseable scope to products in my :with_purchaseable_products

Converting a Rails 2 application to Rails 3, I have to replace the gem searchlogic . Now, using Rails 3.2.8 with the gem Ransack I want to build a search form which uses an existing scope. Example: class Post < ActiveRecord::Base scope :year, lambda { |year| where("posts.date BETWEEN '#{year}-01-01' AND '#{year}-12-31'") } end So far as I know, this can be achieved by defining a custom ransacker . Sadly, I don't find any documentation about this. I tried this in the Post class: ransacker :year, :formatter => proc {|v| year(v) } But this does not work: Post.ransack(:year_eq => 2012).result.to

I have a Collection class which has many coins. I am trying to select collections which have more than two coins. Currently, I have no problem doing that through straight Ruby, but that's extremely inefficient. My current code: collections = Collection.all.select { |c| c.coins.count > 2 } How do I achieve that through a joins call with Arel? Thanks! Yuval Karmi To answer my own question: Collection.joins(:coins).group("coins.collection_id").having("count(coins.id) > 2") Hat tip to KJF who asked this similar question and to krakover for answering it. Add counter_cache columns and query them.

I have a few massive SQL request involving join across various models in my rails application. A single request can involve 6 to 10 tables. To run the request faster I want to use sub-queries in the joins (that way I can filter these tables before the join and reduce the columns to the ones I need). I'm trying to achieve this using ARel. I thought I found the solution to my problem there: How to do joins on subqueries in AREL within Rails , but things must have changed because I get undefined method '[]' for Arel::SelectManager . Does anybody have any idea how to achieve this (without using

I've hit a slight block with the new scope methods (Arel 0.4.0, Rails 3.0.0.rc) Basically I have: A topics model, which has_many :comments , and a comments model (with a topic_id column) which belongs_to :topics . I'm trying to fetch a collection of "Hot Topics", i.e. the topics that were most recently commented on. Current code is as follows: # models/comment.rb scope :recent, order("comments.created_at DESC") # models/topic.rb scope :hot, joins(:comments) & Comment.recent & limit(5) If I execute Topic.hot.to_sql , the following query is fired: SELECT "topics".* FROM "topics" INNER JOIN