magento using join in grid.php prepareCollection

Question

Can someone tell me how to make a join within magento

Here is the problem:

<?//kleurtjes
$collection= Mage::getModel('faq/faq')->getCollection();

$collection->getSelect()->join(array('faqcat' => $this->getTable('faqcat/faqcat')), 'faqcat.faqcat_id=faq.faqcat_id' , array('faqcat.*'));

?>

i am trying to make a join with the table faqcat where i use the key faqcat_id .

futher i want that faqcat.name + faq.faq_id are being selected cos these are the values i want to use in colums.

<?
  protected function _prepareColumns()
  {

      $this->addColumn('faq_id', array(
          'header'    => Mage::helper('faq')->__('ID'),
          'align'     =>'right',
          'width'     => '50px',
          'index'     => 'faq_id',
      ));

      $this->addColumn('name', array(
          'header'    => Mage::helper('faqcat')->__('Titel'),
          'align'     =>'left',
          'index'     => 'name',


      ));

}
?>

after trying 1000 combinations i dont know what to do anymore ... who is willing to help me

this is the complete function:

<?
  protected function _prepareCollection()
  {

     $collection= Mage::getModel('faq/faq')->getCollection();
     //$collection->getSelect()->join(array('faqcat' => $this->getTable('faqcat/faqcat')), 'faqcat.faqcat_id=faq.faqcat_id' , array('faqcat.*'));
     $id = Mage::getModel('customer/session')->getCustomer()->getId();

      $this->setCollection($collection);

     // }
      return parent::_prepareCollection();
  }

?>

just to be clear this is the sql i want to have , but then the magento way

<?//kleurtjes
SELECT faq.faq_id as id, faqcat_name as name
FROM faq
JOIN faqcat
USING ('faqcat_id')
?>

Answer 1

Try this:

$collection->getSelect()
          ->join($this->getTable('faqcat/faqcat'), "faqcat.faqcat_id = main_table.faqcat_id", array(faqcat.*));

You can see the sql that will actually be run to fetch the collection by:

Mage::log($collection->getSelect()->__toString());

The Varien_Db_Select class is based on Zend_Db_Select, so the Zend documentation is a good reference.

Answer 2

i have just started developing magento extension (loving it) and this is the 2nd part in it where i have to show a grid from two tables. (whew). but its not that easy after surfing internet a lot i achieved mine result by doing this.

$collection = Mage::getModel('linkdirectory/linkdirectory')->getCollection();
      $resource = Mage::getSingleton('core/resource');

      $collection->getSelect()
              ->join(
                      array('lk'=>$resource->getTableName('linkdirectory/linkcategory')),
                     'lk.cat_id = main_table.cat_id',
                      array('lk.cat_title','lk.cat_id')
                      );

/* mine was showing this */ /SELECT main_table., lk.cat_title, lk.cat_id FROM linkdirectory AS main_table INNER JOIN linkcategory AS lk ON lk.cat_id = main_table.cat_id*/

/* to print the current query */

$collection->printlogquery(true);exit;