如何在Laravel中做2个SQL字段的减法输出?

Question

我是Laravel和SQL的新手，我被卡住了，我不知道在哪里看。我有3列，end_odometer,start_odometer,km_travel。用户在Laravel页面中输入开始值和结束值，我希望从start_odometer中减去end_odometer并将其存储在km_travel中。

这是我的store控制器:

public function store(Request $request)
{
$count= new VehicleLog();
$count->start_odo = $request->input('start_odo');
$count->end_odo = $request->input('end_odo');

$count->save();
return redirect('/resulttravel')->with('success', 'data added');
}

我不确定km_travel代码应该包含什么。如果有人能给我指出正确的方向，我将不胜感激!

Answer 1

这很简单，你可以这样做:

public function store(Request $request)
{
$count= new VehicleLog();
$count->start_odo = $request->input('start_odo');
$count->end_odo = $request->input('end_odo');
$count->km_travel = $request->input('end_odo') - $request->input('start_odo');
$count->save();
return redirect('/resulttravel')->with('success', 'data added');
}

或:

public function store(Request $request)
{
VehicleLog::create([
'start_odo' => $request->input('start_odo'),
'end_odo' => $request->input('end_odo'),
'km_travel' => $request->input('end_odo') - $request->input('start_odo')
]);
return redirect('/resulttravel')->with('success', 'data added');
}