View in laravel error undefined variable - php

Question

I am a newbie in laravel and php. I cannot show the results of query in laravel. I wrote this in my program.
routes.php
Route::get('books/see', function()
{
return View::make('books.absen');
});
Route::post('books/absen','BookController#absen');
BookController.php
public function absen()
{
$ruang = Input::get('ruangn');
$results = DB::select( DB::raw("SELECT id, name, isbn, ta, tb FROM book WHERE ta = '$ruang'"));
return Redirect::to('books/see');
}
absen.blade.php
<select name="ruangn" class="form-control" method="post" action="{{URL::to('books/absen')}}">
<?php
for( $i=1; $i<19; $i++ )
{
?>
<option>
<?php echo $i;
}
?>
</option>
</select>
<input type="submit" name="submit" value="Oke" class="btn btn-info">
<table class="table table-bordered table-striped">
<thead>
<th>No</th>
<th>Name</th>
<th>ISBN</th>
<th>TA</th>
<th>TB</th>
</thead>
<tbody>
#foreach ($results as $value)
<tr>
<td>{{$value->id}}</td>
<td>{{$value->name}}</td>
<td>{{$value->isbn}}</td>
<td>{{$value->ta}}</td>
<td>{{$value->tb}}</td>
</tr>
#endforeach
</tbody>
</table>
And error is Undefined variable: results (View: ...\absen.blade.php) I very tired with this. Help please

Answer 1

Instead of redirecting, you should render the view in the absen() action. When doing the redirect the data you just selected from the db is all gone.
Try this:
public function absen()
{
$ruang = Input::get('ruangn');
$results = DB::select( DB::raw("SELECT id, name, isbn, ta, tb FROM book WHERE ta = '$ruang'"));
return View::make('books/see')->with('results', $results);
}
Also you need to check if $results exists in your view, since you also want to display it when no results are available
#if(isset($results))
<table class="table table-bordered table-striped">
<thead>
<th>No</th>
<th>Name</th>
<th>ISBN</th>
<th>TA</th>
<th>TB</th>
</thead>
<tbody>
#foreach ($results as $value)
<tr>
<td>{{$value->id}}</td>
<td>{{$value->name}}</td>
<td>{{$value->isbn}}</td>
<td>{{$value->ta}}</td>
<td>{{$value->tb}}</td>
</tr>
#endforeach
</tbody>
</table>
#endif
Attention
André Daniel is very right with his comment. Your code is prone to SQL injection. You should really take a look at Laravels ORM Eloquent or the query builder. At the very minimum, use bindings for parameters:
DB::select(DB::raw("SELECT id, name, isbn, ta, tb FROM book WHERE ta = ?"), array($ruang));
Here's an example with the query builder (Thanks #AndréDaniel)
DB::table("book")->where("ta", $ruang)->get()

Answer 2

You have to make your view with your variable.
Here is what you should do :
routes.php
Route::get('books/see', function()
{
return View::make('books.absen');
});
Route::post('books/absen','BookController#absen');
BookController.php
public function absen()
{
$ruang = Input::get('ruangn');
$results = DB::select( DB::raw("SELECT id, name, isbn, ta, tb FROM book WHERE ta = '$ruang'"));
return View::make('books.absen')->with(array('results' => $results));
}
absen.blade.php
<select name="ruangn" class="form-control" method="post" action="{{URL::to('books/absen')}}">
<?php
for( $i=1; $i<19; $i++ )
{
?>
<option>
<?php echo $i;
}
?>
</option>
</select>
<input type="submit" name="submit" value="Oke" class="btn btn-info">
#if(isset($results))
<table class="table table-bordered table-striped">
<thead>
<th>No</th>
<th>Name</th>
<th>ISBN</th>
<th>TA</th>
<th>TB</th>
</thead>
<tbody>
#foreach ($results as $value)
<tr>
<td>{{$value->id}}</td>
<td>{{$value->name}}</td>
<td>{{$value->isbn}}</td>
<td>{{$value->ta}}</td>
<td>{{$value->tb}}</td>
</tr>
#endforeach
</tbody>
</table>
#endif
By the way, you should use Laravel form functions Forms & HTML