ActiveRecord::Pretty::Comparator

A simple ActiveRecord extension to support where with comparison operators (>, >=, <, and <=).

Installation

Add this line to your application's Gemfile:

gem 'activerecord-pretty-comparator'

And then execute:

$ bundle

Or install it yourself as:

$ gem install activerecord-pretty-comparator

Usage

posts = Post.order(:id)

posts.where("id >": 9).pluck(:id)  # => [10, 11]
posts.where("id >=": 9).pluck(:id) # => [9, 10, 11]
posts.where("id <": 3).pluck(:id)  # => [1, 2]
posts.where("id <=": 3).pluck(:id) # => [1, 2, 3]

Why not `Post.where("id > ?", 1)` ?

As a main contributor of the predicate builder area, @kamipo recommends using the hash syntax, the hash syntax also have other useful effects (making boundable queries, unscopeable queries, hash-like relation merging friendly, automatic other table references detection).
ref: rails/rails#39863 (comment)

Merge examples

# it doesn't work
# SELECT `posts`.`id` FROM `posts` WHERE (id > 1) AND `posts`.`id` = ?  [["id", 1]]
Post.where("id > ?", 1).merge(Post.where(id: 1)).pluck(:id) # []

# it works
# SELECT `posts`.`id` FROM `posts` WHERE `posts`.`id` = ?  [["id", 1]]
Post.where("id >": 1).merge(Post.where(id: 1)).pluck(:id) # [1]

Unscope examples

# it doesn't work
# SELECT `posts`.* FROM `posts` WHERE (id > 1)
Post.where("id > ?", 1).unscope(where: :id)

# it works
# SELECT `posts`.* FROM `posts`
Post.where("id >": 1).unscope(where: :id)

Precision examples

From type casting and table/column name resolution's point of view, where("created_at >=": time) is better alternative than where("created_at >= ?", time).

class Post < ActiveRecord::Base
  attribute :created_at, :datetime, precision: 3
end

time = Time.now.utc # => 2020-06-24 10:11:12.123456 UTC

Post.create!(created_at: time) # => #<Post id: 1, created_at: "2020-06-24 10:11:12.123000">

# SELECT `posts`.* FROM `posts` WHERE (created_at >= '2020-06-24 10:11:12.123456')
Post.where("created_at >= ?", time) # => []

# SELECT `posts`.* FROM `posts` WHERE `posts`.`created_at` >= '2020-06-24 10:11:12.123000'
Post.where("created_at >=": time) # => [#<Post id: 1, created_at: "2020-06-24 10:11:12.123000">]

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/technuma/activerecord-pretty-comparator.

License

The gem is available as open source under the terms of the MIT License.

Special thanks

@kamipo 🙇

Original idea: https://blog.kamipo.net/entry/2021/01/14/191753 (ja)