SELECT DISTINCT users.*, 
(SELECT SUM(forecasts.bet * forecasts.coefficient) - SUM(forecasts.bet) FROM forecasts, events where users.id = forecasts.user_id AND events.id = forecasts.event_id AND events.status = 2) / SUM(forecasts.bet) as roi
FROM users, forecasts, events
WHERE users.id = forecasts.user_id
AND events.id = forecasts.event_id
GROUP BY users.id

$users = User::select([
    'users.*',
    'last_posted_at' => Post::selectRaw('MAX(created_at)')
            ->whereColumn('user_id', 'users.id')
])->get();

$users = User::select([
    'users.*',
    'last_posted_at' => Post::selectRaw('MAX(created_at)')
            ->whereColumn('user_id', 'users.id')
])->withCasts([
    'last_posted_at' => 'date'
])->get();