如何在雄辩的laravel中编写此查询？

I have been trying to figure out how to write this using Eloquent? This is as far as I got, any suggestions?

 $budgets = Budget::join('transactions','budgets.id','=','transactions.category')
                  ->where('transactions.user_id','=', $authId)
                  ->groupby('transactions.category')
                  ->sum('budgets.amount','-','transactions.amount');

Query that works below

  SELECT SUM(budgets.amount) - SUM(transactions.amount) as amount,
         budgets.category
    FROM budgets 
    JOIN transactions
      ON budgets.id = transactions.category
GROUP BY category

You were close, but when you're getting multiple columns and math, or semi-complicated math (i.e. not a simple sum) you want to pass the math along as a separate column in a raw statement.

Budgets::join('transactions', 'budgets.id', '=', 'transactions.category')
    ->select([
        DB::raw('SUM(budgets.amount) - SUM(transactions.amount) as amount'), 
        'budgets.category'
    ])
    ->where('transactions.user_id','=', $authId)
    ->groupBy('budgets.category')
    ->get();