Question

我正在尝试计算两列值但我收到以下错误。发票和付款之间的减少是算术运算。你能帮我吗？

Controller.php这样

public function getIndex( Request $request )
{
$this->data['balanceTotal'] = \DB::table('tb_accounts')->select('sum(invoice-payment)')->get();
return view('account.index',$this->data);
}

Index.blade.php

{{ $balanceTotal }}

错误

SQLSTATE [42S22]：找不到列：1054未知列＆＃39;和（发票支付）＆＃39;在＆＃39;字段列表＆＃39; （SQL：选择来自sum(invoice-payment)）的tb_accounts

Answer 1

你需要一个原始表达式：

\DB::table('tb_accounts')->select(\DB::raw('sum(invoice)'))

但是，我想你需要总结invoice和payment：

\DB::table('tb_accounts')->select(\DB::raw('(invoice - payment) AS amount'))

请参阅文档：https://laravel.com/docs/5.5/queries#raw-expressions

注意：避免列名中的minus或使用反向标记（Do minus sign in mysql table column names cause issues?）

Answer 2

这将解决您的问题

<Route path="/login" component={Login} />
      <Route path="/logout" component={Login} />

您收到此错误use Illuminate\Support\Facades\DB; DB::table('tb_accounts')->select(\DB::raw('(invoice + payment) AS amount'))

因为如果你需要在你的视图中传递数组，你正在传递数组来代替字符串尝试像这样返回


htmlentities() expects parameter 1 to be string, array given (View: /home/unive/public_html/sistem/resources/views/accounts/inde‌x.blade.php)

然后在return view('account.index')->withdata($data);

中使用

index.blade.php

Laravel - 算术运算

2 个答案: