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Konnor Rogers
Konnor Rogers

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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
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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 })
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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 })
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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

# 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 })
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Final Syntax

The syntax for attachments is fairly straightforward like so:

ModelName.left_joins(:<attachment_name>_attachment[s]).where(active_storage_attachments: { <column>: <value> })
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And thats it! Good luck and enjoy your new found query power!

Latest comments (2)

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)

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