DEV Community πŸ‘©β€πŸ’»πŸ‘¨β€πŸ’»

Konnor Rogers
Konnor Rogers

Posted on

Querying ActiveStorage Attachments

The problem

You want to find all the ActiveRecord models that either do / do not have a record attached to them.

The solution

Let's say you have a Post class which has one image attached like so:

class Post < ApplicationRecord
  has_one_attached :image
end
Enter fullscreen mode Exit fullscreen mode

To query for all Posts that do not have an image attached the syntax would look like this:

Post.left_joins(:image_attachment).where(active_storage_attachments: { id: nil })
Enter fullscreen mode Exit fullscreen mode

This will return all posts that do not have an image. If you want to find all posts that have an image attached, you would use a #not clause in there like so:

Post.left_joins(:image_attachment).where.not(active_storage_attachments: { id: nil })
Enter fullscreen mode Exit fullscreen mode

has_many_attached

This can even be extended to has_many_attached by using the plural form of :image_attachment like so:

class Post < ApplicationRecord
  has_many_attached :images
end

# Query for all without attachments
Post.left_joins(:image_attachments).where(active_storage_attachments: { id: nil })

# Query for all with attachments
Post.left_joins(:image_attachments).where.not(active_storage_attachments: { id: nil })
Enter fullscreen mode Exit fullscreen mode

Final Syntax

The syntax for attachments is fairly straightforward like so:

ModelName.left_joins(:<attachment_name>_attachment[s]).where(active_storage_attachments: { <column>: <value> })
Enter fullscreen mode Exit fullscreen mode

And thats it! Good luck and enjoy your new found query power!

Top comments (2)

Collapse
 
sidran83 profile image
Pierre Deveix

Thanks for your post, it was very useful for me!
I just have something to add:
In my case, when the Post Model has many attached images, the query will be
Post.left_joins(:images_attachments).where(active_storage_attachments: { id: nil })
(the attachment_name must be in plural)

Stop sifting through your feed.

Find the content you want to see.

Change your feed algorithm by adjusting your experience level and give weights to the tags you follow.