how to pull all images from a hash field?

Question

I have an Activity_Part model with a field called activity_json. this field is a hash that has a key named "image". I want to query/select only the ID of all Activity_Part only with activity_json field with key "image"

ActivityPart < ApplicationRecord {
               :id => :integer,
         :owner_id => :integer,
    :activity_type => :string,
    :activity_json => :json,

I thought of doing something like this:

x = ActivityPart.all
x.pluck(activity_json: 'image')

but I don't know how to return just the Activity ID with all the images in the activty_json field

Answer 1

I'll assume that you're using postgres.

jsonb type has the ? operator which can be used like this: ActivityPart.where("activity_json ? 'image'") as per documentation.

If your column is of a json type then consider changing it to jsonb. You can alternatively cast it to jsonb in the query like so: ActivityPart.where("activity_json::jsonb ? 'image'") but be aware that this might negatively affect the performance of the query.