title: missing FROM-clause entry for table "Grupo" cakephp
body: <p>hi i have  aproblem in my code, I want generate a list of user but this have a group and need just a group of user.
  the error say:</p>
  
  <blockquote>
    <p>Error: SQLSTATE[42P01]: Undefined table: 7 ERROR: missing FROM-clause entry for table "Grupo"</p>
  </blockquote>
  
  <p>this is my code:</p>
  
  <pre><code>    public function add()
  {
      $this-&gt;loadModel('SoyaProveedor');
      $this-&gt;loadModel('Soya');
  
      $this-&gt;set('oleaginosas', $this-&gt;Soya-&gt;find('list', array(
          'fields'=&gt; array('id','username'),
          'conditions' =&gt; array('Grupo.categoria' =&gt; 'Soya' , 'Grupo.subcategoria' =&gt; 'Productor de Oleaginosas')
          )));
  
      if ($this-&gt;request-&gt;is('post')) {
      $this-&gt;request-&gt;data['SoyaProveedor']['nombre'] = strtoupper($this-&gt;request-&gt;data['SoyaProveedor']['nombre']);
      $this-&gt;request-&gt;data['SoyaProveedor']['codigo'] = strtoupper($this-&gt;request-&gt;data['SoyaProveedor']['codigo']);
      if ($this-&gt;SoyaProveedor-&gt;save($this-&gt;request-&gt;data)) {
          $this-&gt;Session-&gt;setFlash(__('La Información fue Guardada.'));
          return $this-&gt;redirect(array('action' =&gt; 'index'));
          }
      }
  }
  </code></pre>
  
  <p>the sql query of the cake generate it:</p>
  
  <blockquote>
    <p>SQL Query: SELECT "Soya"."id" AS "Soya__id", "Soya"."username" AS
    "Soya__username" FROM "public"."users" AS "Soya" WHERE
    "Grupo"."categoria" = 'Soya' AND "Grupo"."subcategoria" = 'Productor
    de Oleaginosas'</p>
  </blockquote>