Function sqlx::query_scalar

pub fn query_scalar<DB, O>(
    sql: &'q str
) -> QueryScalar<'q, DB, O, <DB as HasArguments<'q>>::Arguments> where
    DB: Database,
    (O,): for<'r> FromRow<'r, <DB as Database>::Row>, 

Make a SQL query that is mapped to a single concrete type using FromRow.