如何显示具有相同值的最后一行的总数？ （拉拉维尔）

Question

我的 dtaabse 中有表“transaction_items”，看起来与此类似...

id	transaction_id	qty	unit_price
1	100	1	10.00
1	100	2	10.00
1	100	3	10.00
1	200	1	20.00
1	200	1	20.00
1	300	1	15.00

当前我获取数据： $data['transaction_items'] = DB::table('transaction_items')->get();

并运行一个 foreach 循环：

foreach ($transaction_items as $trans) {
 <tr>
  <td> {{ $trans->transaction_id}} </td>
  <td> {{ $trans->qty}} </td>
  <td> {{ $trans->unit_price}} </td>
  <td> * WHOLE TRANSACTION TOTAL</td>

这会像您期望的那样完美地输出数据。虽然我输出的最后一个值 (*WHOLE TRANSACTION TOTAL) 正在运行另一个查询和 foreach 循环以获取整个事务的“总数”。

<tr>
 <td>
  <?php 
  $totals = DB::table('transaction_items')->select('qty', 'unit_price')->where('transaction_id', '=', $trans->transaction_id)->get();
  $ftot = 0;
  foreach ($totals as $total) {
    $ftot += $total->qty * $total->unit_price;
  }
  echo '&pound;'.number_format($ftot, 2);
  ?>
 </td>
</tr>

我知道这可能是错误的做法，但这就是我的原因。

我当前的输出看起来像这样......

transaction_id	qty	unit_price	Trans Total
100	1	10.00	60.00
100	2	10.00	60.00
100	3	10.00	60.00
200	1	20.00	40.00
200	1	20.00	40.00
300	1	15.00	15.00

我希望它看起来像这样，它显示具有相同 transaction_id 的最后一行之后的总数。

transaction_id	qty	unit_price	Trans Total
100	1	10.00
100	2	10.00
100	3	10.00	60.00
200	1	20.00
200	1	20.00	40.00
300	1	15.00	15.00

希望这是有道理的，并提前感谢。

额外编辑

我曾尝试使用“减少”方法，但得到...

$totals = DB::table('transaction_items')
    ->select('qty', 'unit_price')
    ->where('transaction_id', '=', $trans->transaction_id)
    ->get()
    ->groupBy('transaction_id')->each(function($item) {
    $sum = $item->reduce(fn($carry, $product) => $carry + ($product['qty'] * $product['unit_price']));
    $lastRow = $item->pop();
    $lastRow['sum'] = $sum;
    $item->push($lastRow);
    return $item;
})->flatten(1);

$ftot = 0;     
foreach ($totals as $total) {
 $ftot += $total->qty * $total->unit_price;
} 
echo '£'.number_format($ftot, 2);

但我收到此错误： Cannot use object of type stdClass as array

如果我在 original $totals 上执行“print_r”，这是其中一行的示例..

Illuminate\Support\Collection Object ( 
 [items:protected] => Array ( 
  [0] => stdClass Object ( 
   [transaction_id] => 20940 
   [qty] => 4.00 
   [unit_price] => 80.0000 
  ) 
  [1] => stdClass Object ( 
   [transaction_id] => 20940 
   [qty] => 6.00 
   [unit_price] => 10.0000 
  ) 
  [2] => stdClass Object ( 
   [transaction_id] => 20940 
   [qty] => 308.00 
   [unit_price] => 0.4000 
  ) 
  [3] => stdClass Object ( 
   [transaction_id] => 20940 
   [qty] => 308.00 
   [unit_price] => 0.0500 
  ) 
  [4] => stdClass Object ( 
   [transaction_id] => 20940 
   [qty] => 1.00 
   [unit_price] => 10.3000 
  ) 
 ) 
)

Answer 1

简单——Laravel collections 功能强大

$total = $total->reduce(function ($carry, $item) {
    return $carry + ($item->qty * $item->unit_price);
});

或者内联（这段代码我没查过，可能不行）

$total = $total->reduce(fn ($carry, $item) => $carry + ($item->qty * $item->unit_price));

---

更新

我没有正确阅读问题，抱歉。但是收藏仍然很强大。顺便说一句，我认为，您必须考虑这种行为 - 更好的方法是添加一个维度 - 按事务分组并为每个组添加小计

$totals = DB::table('transaction_items')
    ->select('qty', 'unit_price')
    ->where('transaction_id', '=', $trans->transaction_id)
    ->get()
    ->groupBy('transaction_id')->each(function($item) {
        $sum = $item->reduce(fn($carry, $product) => $carry + ($product['qty'] * $product['unit_price']));
        $lastRow = $item->pop();
        $lastRow['sum'] = $sum;
        $item->push($lastRow);
        return $item;
})->flatten(1);