(laravel eloquent) 获取最接近的值（小费游戏）

Question

我创建了一个小费游戏，用户可以猜测一个值，12 小时后，USD/EUR 请求将采用当前的 USD/EUR 费率，给出最接近小费的获胜者将获胜（仅一个赢家，如果 n 个用户给了相同的小费，他们都会赢）。

如何从数据库中获取 "nearest" 小费？

            foreach ($rounds_closed as $round_closed)
        {
            //get latest rate
            $amount = 458.12;

            //set transaction as processed and set latest rate
            $round_closed->update([
                'status'    => 2,
                'win_tip'   => $amount,

                ]);

            //get lucky winners
    //here I would need eloquent code to choose the "nearest" winners
            $winners_transactions = Transaction::where('round_id', $round_closed->id)->where('assessment', $round_closed->win_tip)->get();

            //if we have at least one winner
            if ($winners_transactions->count() > 0) 
            {
                //calculate their win amount
                $sum = $round_closed->transactions->sum('amount');
                $fee = $sum * 0.10;

                $sum = $sum - $fee;

                $sum = number_format($sum / $winners_transactions->count(), 8, '.', '');

                foreach ($winners_transactions as $winner_transaction)
                {
                    //mark transaction as payed out
                    $winner_transaction->update([
                        'payout'    => 1,
                        ]);

                    //payout user


                }

            }                
        }

Answer 1

我不熟悉你框架中的语法，但是 SQL 中有一个你可以重构的可能方法：

SET @amount = 458.12;

#Order tips by smallest difference and return the first result
SET @winning_tip = (SELECT tip FROM tips ORDER BY ABS(tip-@amount) ASC LIMIT 1);

#Return all users with the winning tip value 
SELECT userid, tip, ABS(tip-@amount) AS delta FROM tips WHERE tip = @winning_tip

http://sqlfiddle.com/#!9/fac65/2

根据您的数据大小，您还可以撤回所有事务并在 SQL.

之外编写上述逻辑

主要是您需要确定哪个小费最接近金额，并将其用作 select/filter 获胜者的参数。

(laravel eloquent) 获取最接近的值（小费游戏）

(laravel eloquent) get nearest values (tipping game)

sql

orm

nearest-neighbor

eloquent

laravel-5.2