query.sum() should be generic

[MihaelIsaev]

Trying to get sum of money movements by calling

MoneyMovement.query(on: conn).sum(\MoneyMovement.quantity).flatMap { sumOfIncomes -> EventLoopFuture<Int64> in
    //somehow `sumOfIncomes` is Double, that's strange because `MoneyMovement.quantity` is Int64
}

but getting error

[ ERROR ] PostgreSQLError.binaryFloatingPoint: Could not decode Double from binary data type: NUMERIC.

[MihaelIsaev]

Tried to change MoneyMovement.quantity column type to double precision in the database and variable type to Double in the Model, but getting the same error.. looks like .sum() is completely broken

[MrMage]

Related: vapor/fluent#450 (comment)

Also, I think this (at least partially) affects Fluent itself, not Postgres specifically.

[tanner0101]

As of 1.0.0, sum(...) will be the same type as the field it is called on.