CODEWITHSUNDEEP
elixirphoenix-frameworkecto
cjm2671
cjm2671

Reputation: 19456

Adding a virtual field to an object

  def list_links_count do

    query = 
      from l in Link,
        join: c in Click, as: :click,
        where: c.link_id == l.id,
        group_by: l.id,
        select: {l, count(l.id)}

    query |> Repo.all

  end

I've got a function that counts that number of clicks per link. The problem is with the final data structure, which is of the form {Link, 10}. What I'd really like to do is have it put_in the total, so I can access it more easily in a view, something like link.click_count. Is that possible?

Upvotes: 3

Views: 320

Answers (2)

Aleksei Matiushkin
Aleksei Matiushkin

Reputation: 120990

Use Kernel.elem/2:

{Link, 10} |> elem(1) 
#⇒ 10

So, within your code:

query
|> Repo.all()
|> how_do_you_get_tuple()
|> elem(1)

Upvotes: 1

Brett Beatty
Brett Beatty

Reputation: 5963

Do you have the virtual field on your Ecto schema for Link? If not, you'll want to add it:

field(:click_count, :integer, virtual: true)

Then your select could look something like this:

select: %{l | click_count: count(l.id)}

Since you now have a click_count key in your Link structs, you can put that key and still have a list of Links. So you should be able to access link.click_count.

Upvotes: 2

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