CODEWITHSUNDEEP
ruby-on-railsactiverecordruby-on-rails-4
hungrythirstycircle
hungrythirstycircle

Reputation: 21

Ruby on rails - Active Record Query - remove all duplicate records

I have a Project object, which has multiple comments.

I can easily get all comments for the project by using @project.comments

However, I would like to filter out all non unique comments for that project.

For instance if there are two comments which both say "Hello world.", I don't want either of them to be in my results.

Also, I want the resulting array to be an array of comment objects not just one attribute of the comment object.

I have currently come up with the following solution

unique_comments_for_project = []
@project.comments.each do |comment|
   if @project.comments.where(:text => comment.text).size < 2
      unique_comments_for_project << comment
   end
end

However, this solution seems to be extremely inefficient. Is there a better Ruby on Rails way of doing this?

N.B. The problem with @project.comments.select('distinct text') is that it provides one of the duplicates in the results. I don't want any duplicates.

Upvotes: 2

Views: 826

Answers (1)

Raj
Raj

Reputation: 22926

Group the comments by text and filter using having clause.

@project.comments.select('text').group('text').having('count(distinct text) = 1')

Upvotes: 2

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