code: public function queryExists()
  	{
  		foreach ($this->selects as $select)
  		{
  			$result = $select->queryExists();
  
  			if (is_null($result) || $result)
  			{
  				return $result;
  			}
  		}
  
  		return false;
  	}
docs: Execute a SELECT EXISTS On each query. Will stop when at least one query returns true.
  @return bool|null Null on error