如何用laravel选择计数

I want to show the amount of data stored on the database tables using Laravel v 4.2.0 but i have a problem with using function count(). here's my code :

$total = DB::select("select count(*) from rents left join operators on operators.code = rents.code where (operators.code is null) and rents.booking = 'N'");    
echo $total;

the message error say :

Syntax error or access violation

can anyone help me?

Try this:

$total = DB::select(DB::raw("select count(*) as cnt from rents left join operators on operators.code = rents.code where (operators.code is null) and rents.booking = 'N'"));    
echo $total[0]->cnt;

Try Debugging:

echo "<pre>";
print_r($total);
echo "</pre>";
exit;

See, if that helps.