Question about querying a money_with_currency column using Ecto

[scmx]

Hi, I'm having trouble figuring out how to query a database column with the money_with_currency Money.Ecto.Composite.Type postgres type using Ecto.

MyApp.Repo.get_by(MyApp.Transaction, amount: Money.new(3000, :SEK))

[debug] QUERY ERROR source="transactions" db=2.0ms
SELECT e0."id", e0."amount", e0."inserted_at", e0."updated_at" FROM "transactions" AS e0 WHERE (e0."amount" = $1) [{"SEK", #Decimal<3000>}]
** (FunctionClauseError) no function clause matching in Ecto.Adapters.Postgres.TypeModule.encode_tuple/5

The following arguments were given to Ecto.Adapters.Postgres.TypeModule.encode_tuple/5:

    # 1
    {"SEK", #Decimal<3000>}

# 2 1

    # 3
    nil

    # 4
    {Ecto.Adapters.Postgres.TypeModule, #Reference<0.3714461165.225312769.164420>}

    # 5
    []

Attempted function clauses (showing 3 out of 3):

    defp encode_tuple(tuple, n, [oid | oids], [type | types], acc)
    defp encode_tuple(tuple, n, [], [], acc) when tuple_size(tuple) < n
    defp encode_tuple(tuple, _, [], [], _) when is_tuple(tuple)

(ecto) lib/postgrex/type_module.ex:715: Ecto.Adapters.Postgres.TypeModule.encode_tuple/5
(ecto) /myapp/deps/postgrex/lib/postgrex/type_module.ex:715: Ecto.Adapters.Postgres.TypeModule.encode_params/3
(postgrex) lib/postgrex/query.ex:45: DBConnection.Query.Postgrex.Query.encode/3
(db_connection) lib/db_connection.ex:1079: DBConnection.describe_run/5
(db_connection) lib/db_connection.ex:1150: anonymous fn/4 in DBConnection.run_meter/5
(db_connection) lib/db_connection.ex:1207: DBConnection.run_begin/3
(db_connection) lib/db_connection.ex:592: DBConnection.prepare_execute/4
(ecto) lib/ecto/adapters/postgres/connection.ex:73: Ecto.Adapters.Postgres.Connection.prepare_execute/5
(ecto) lib/ecto/adapters/sql.ex:256: Ecto.Adapters.SQL.sql_call/6
(ecto) lib/ecto/adapters/sql.ex:426: Ecto.Adapters.SQL.execute_and_cache/7
(ecto) lib/ecto/repo/queryable.ex:133: Ecto.Repo.Queryable.execute/5
(ecto) lib/ecto/repo/queryable.ex:37: Ecto.Repo.Queryable.all/4
(ecto) lib/ecto/repo/queryable.ex:70: Ecto.Repo.Queryable.one/4

---

Then I tried this instead
import Ecto.Query; MyApp.Repo.all(from t in MyApp.Transaction, where: t.amount == ^Money.new(3000, :SEK))
import Ecto.Query; MyApp.Repo.all(where MyApp.Transaction, [t], t.amount == ^Money.new(3000, :SEK))
they both give the same error.

I'm guessing there's just a small change in my code needed? I'd be happy to improve docs if needed.

I'm wondering if could code by added to the Money.Ecto.Composite.Type to support passing in a money struct as is? If possible I'd guess that https://hexdocs.pm/ecto/Ecto.Type.html or https://hexdocs.pm/ecto/Ecto.Query.html should give a clue as to how.

[scmx]

Here's a few ways using fragment() with raw SQL that does work:
Repo.all(from t in Transaction, where: t.amount == fragment("('SEK', 3000)::money_with_currency"))
Repo.all(from t in Transaction, where: t.amount == fragment("(?, ?)::money_with_currency", "SEK", 3000))
But there's better way right? 😀 🤔

[scmx]

import Ecto.Query; MyApp.Repo.all(from t in MyApp.Transaction, where: t.amount == type(^Money.new(3000, :SEK), t.amount))
I got this solution from @LostKobrakai in Elixir Slack. Thanks!

So, to sum it up, if you have a money variable like this amount = ~M[3000]SEK and try to pass it in to a query, you might find this diff useful:

- where: t.amount == ^amount
+ where: t.amount == type(^amount, t.amount)

[scmx]

Closing since my use case is solved. Still would be great if it was possible without doing this as well