How to count total string value / group using an Active Record query?

Question

Is there a way to count how many specific string value from the database column using Active Record (Using PostgreSQL as my database)?

If I wanted to show in my view the how many taco lovers there are in the world.

For example:

# Where the number "2" was an ActiveRecord count in the Persons table
# reading from the column named "favorite_food"

<div class="notice">
  <p>There are 2 burrito lovers online</p>
</div>

From looking around the ActiveRecord documentation I got to this:

# == Schema Information
#
# Table name: Persons
#
#  id                     :integer          not null, primary key
#  name                   :string           default(""), not null
#  age                    :integer          default(""), not null
#  favorite_food          :string

# Data
# Person id: 1, name: "John", age: "18", favorite_food: "taco"
# Person id: 2, name: "Jane", age: "19", favorite_food: "taco"
# Person id: 3, name: "Bill", age: "20", favorite_food: "burrito"
# Person id: 4, name: "Beth", age: "21", favorite_food: "nacho"

# This will record total unique foods
Person.count(:favorite_food)
=> 3

# This will return a hash with total name of distinct foods
Person.group(:favorite_food).count
=> {taco=>"2", "burrito"=>1, "nacho"=>1}

I think the last bit is closer but I wanted to query a specific food type, how would I do this with ActiveRecord if this is possible? I was thinking I could iterate using enum but this would be not the best way to tackle this situation.

Thanks for taking the time to take a look at my question.

Answer 1

尝试这个

Person.where(favorite_food: 'burrito').count