Requery using join

I make 2 queries.

The first:

@queue = Attempt.joins({:problem_info => [:problem, :contest]},
:user).where(‘’ => 1).limit(100)

The second:

queue = ActiveRecord::Base.connection.query("
SELECT pi.number, “pname”,, a.result, a.exec_time,
a.used_memory, a.time - c.start_time “time”
FROM attempts a
INNER JOIN problem_infos pi ON ( = a.problem_info_id)
INNER JOIN problems p ON ( = pi.problem_id)
INNER JOIN users u ON ( = a.user_id)
INNER JOIN contests c ON ( = pi.contest_id)
WHERE (pi.contest_id = 1)
ORDER BY a.time DESC;")

The first query is better and it is write easy, but it makes several
small requery to database. If i am right, i use resources of Ruby on
The seond query make one requery to database.

I want to use the first query, but it works longer than the second. How
to right query, using “join”, but it mustn’t make several requery.