Php mysqli Call to a member function fetch_all() on boolean : <p>It is my code:</p>

<pre><code>    public function getEmployees($where='1',$start, $perPage){
    $sql="SELECT e.name,e.birthday,d.title_dep,p.title_pos,t.title_type,e.salary FROM `employees` AS e INNER JOIN departments AS d ON e.id_dep=d.id
  INNER JOIN positions AS p ON e.id_pos=p.id
  INNER JOIN payment_types AS t ON e.id_type=t.id  where ".$where. 'LIMIT 10';
</code></pre>

<p>I always get error: <strong>Call to a member function fetch_all() on boolean</strong> </p>

<p>It began when I added 'LIMIT 10'. Whithout it my code works fine. 
How can I solve my problem?</p>
