Find all records which have a count of an association greater than zero

Question

I\'m trying to do something that I thought it would be simple but it seems not to be.

I have a project model that has many vacancies.

class Project &         


        

Answer 1

1) To get Projects with at least 1 vacancy:

Project.joins(:vacancies).group('projects.id')

2) To get Projects with more than 1 vacancy:

Project.joins(:vacancies).group('projects.id').having('count(project_id) > 1')

3) Or, if Vacancy model sets counter cache:

belongs_to :project, counter_cache: true

then this will work, too:

Project.where('vacancies_count > ?', 1)

Inflection rule for vacancy may need to be specified manually?