$dataProvider=new CActiveDataProvider('Post');
$this->widget('zii.widgets.grid.CGridView', array(
  'dataProvider'=>$dataProvider,
));

$this->widget('zii.widgets.grid.CGridView', array(
  'dataProvider'=>$dataProvider,
  'columns'=>array(
    'title',     // display the 'title' attribute
    'category.name', // display the 'name' attribute of the 'category' relation
    'content:html',  // display the 'content' attribute as purified HTML
    array(      // display 'create_time' using an expression
      'name'=>'create_time',
      'value'=>'date("M j, Y", $data->create_time)',
    ),
    array(      // display 'author.username' using an expression
      'name'=>'authorName',
      'value'=>'$data->author->username',
    ),
    array(      // display a column with "view", "update" and "delete" buttons
      'class'=>'CButtonColumn',
    ),
  ),
));