title: how to detect if a field has input in laravel
body: <p>I was trying to create a validation in laravel controller, where if one of the fields has input, then it will validate the rest of the fields to be <code>'required'</code>. But it prompts <code>Error
  Class 'Illuminate\Support\Facades\Input' not found</code>. Please help</p>
  
  <pre><code>         if(Input::has('quantity1') || has('unit1') || has('dimension1') || has('price1')){
              $data = $request-&gt;validate([
                      'quantity1' =&gt; 'required',
                      'unit1' =&gt; 'required',
                      'dimension1' =&gt; 'required',
                      'price1' =&gt; 'required',
                  ]);
  </code></pre>