Is it possible to pluck from multiple tables?

[axelson]

Say I have the following schema:

User has many Post
Post has many Comment
Comment belongs to EmailAddress

I can easily do Post.where(user_id: user_id).pluck_to_hash which will get me all the fields of the Post. But what if I want to also get the fields of the Comments and EmailAddresses as well?

[rasmar]

You can try something like Post.joins([:comment]).where(user_id: user_id).pluck_to_hash(:first_post_column, :second_post_column, "comments.first_column as comments_first_column", "comments.second_column as comments_second_column") same thing apply to deeper nested EmailAddress . Join that table as well and retrive fields.

[probablykabari]

@axelson pluck actually takes any valid SQL, so you can do .pluck('table.id, other_table.some_column'). This should work with this gem as well.

[feliperaul]

@RipTheJacker is correct. Also, you can alias the keys for a better result. For instance:

User.left_joins(properties: :location).distinct.limit(100).pluck_h("users.id as users_id", "locations.city as city")

Returns an array of:
{"users_id"=>2, "city"=>"Curitiba"}

This way, pluck_s (to Struct) also works flawlessly, because otherwise you would have structs with users.id methods on them, which would only be callable if you used .send("users.id"), which would defeat the point.