Why Am I Getting An Unbound Variable Message On This Ecto Query?

Question

Hey I am trying to make a query, my code look like this:

  def show(conn, _params) do
user = Guardian.Plug.current_resource(conn)
team = Web.get_team!(user.team.id)

score_query =
  from(
    u in User,
    where: u.team.id == team.id,
    select: sum(u.score)
  )

team_score = Repo.all(score_query)

IO.puts("score")
IO.inspect(team_score)

conn |> render("team.json", team: team)

And when I try to run it, I am getting an error that says:

** (Ecto.Query.CompileError) unbound variable `team` in query

but why is that unbound? How can I fix it and why is it happening?

score 6 · Accepted Answer · answered Aug 23 '18 at 04:59

6

You should pin (^) team.id:

score_query =
  from(
    u in User,
    #                   ⇓ HERE
    where: u.team.id == ^team.id,
    select: sum(u.score)
  )

As per Ecto.Query documentation:

External values and Elixir expressions can be injected into a query expression with ^:
def with_minimum(age, height_ft) do
  from u in "users",
    where: u.age > ^age and u.height > ^(height_ft * 3.28),
    select: u.name
end

answered Aug 23 '18 at 04:59

Aleksei Matiushkin

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Hey, how can that be that if i have more than one lines that it should add up the result just says /v and no error? – jhonathan myers Aug 23 '18 at 05:37
I am not sure I follow. Could you please provide an example? – Aleksei Matiushkin Aug 23 '18 at 05:38
ok it seems random, I have a score of 5, i added 6 to it it gae the /v as a result, then i changed it to 12 and it worked the result as 17, and then i chnaged it back and the result was /n – jhonathan myers Aug 23 '18 at 05:41
I still do not follow. You probably have some context that I lack. – Aleksei Matiushkin Aug 23 '18 at 05:43
i see the scores in the database nicely as they are integers, and i get the sum of them as you see above, but as a result when I call IO.inspect the results are like '/a', '/n', '/v' for some reason – jhonathan myers Aug 23 '18 at 05:45
1

Ah. That’s the common famous surprise for newcomers :) https://stackoverflow.com/questions/30037914/elixir-lists-interpreted-as-char-lists (if you were to put proper backslash instead of forward slash I could get the issue sooner.) – Aleksei Matiushkin Aug 23 '18 at 05:50
oh so it means that the value is correct, just IO.inspect tries to help too much? – jhonathan myers Aug 23 '18 at 05:52
1

Yes, the value is correct. `IO.inspect` does not try anything, they are literally equal: `'\n' == [10] #⇒ true`. – Aleksei Matiushkin Aug 23 '18 at 05:53

Why Am I Getting An Unbound Variable Message On This Ecto Query?

1 Answers1