Is it possible to make a Queryable out of a primitive?

[wt]

I use Postgresql. I have a table with a numeric id, like so:

CREATE TABLE atable
(
    id integer NOT NULL GENERATED ALWAYS AS IDENTITY,
    name character varying(100) NOT NULL,
    CONSTRAINT atable_pkey PRIMARY KEY (id)
)

And I want to just get a list of ids. I have defined this struct:

#[derive(Debug, Queryable, Selectable)]
#[diesel(table_name = crate::schema::atable)]
#[diesel(check_for_backend(diesel::pg::Pg))]
struct ATableId ( #[diesel(column_name = "id")] pub i64 )

Is there any way that I could just define a Selectable on a primitive?

Something like this might be kinda cool if it does not exist:

#[derive(Debug, Queryable, Selectable)]
#[diesel(table_name = crate::schema::atable)]
#[diesel(check_for_backend(diesel::pg::Pg))]
#[diesel(column_name = "id")]
type UserId i64;

[wt]

Okay, so I found this:

let a: Vec<i32> = atable::table.select(a_dsl::id).load(&mut conn).await?;

Is there some clever way to do this so that I don't have to explicitly type the variable? Or at least so that I only have to specify the i32 and not the Vec part of the type?

[wt]

And I found it:

let a = atable::table.select(a_dsl::id).load::<i32>(&mut conn).await?;