View difference between Paste ID: q7D2k7XG and LnB54Cpy

 public function rules() {
         return array(
             array('name, email, subject, message', 'required', 'message' => Yii::t('app', 'MSG_ATTRIBUTE_BLANK')),
             array('email', 'email'),
             array('verifyCode', 'CaptchaExtendedValidator', 'allowEmpty' => !CCaptcha::checkRequirements(), 'on' => 'fContact'),
-            array('name, email,subject,message', 'safe','lastactivity', 'on' => 'search'),
+            array('name, email,subject,message,lastactivity', 'safe', 'on' => 'search'),
             array('name, subject, email, message, status,createdon,updatedon,verifyCode,lastactivity', 'safe'),
         );
     }
  public function relations() {
         return array(
             'ca' => array(self::HAS_MANY, 'ContactAction', 'contact_id'),
 	);
 }
 
 public function search() {
         $criteria = new CDbCriteria;
         $lastactivity_sql = '(select max(date) from tbl_contact_action where contact_id=t.contact_id)';
         $criteria->select = array('t.*', $lastactivity_sql . ' as lastactivity');
         $criteria->addCondition('t.status<>"Deleted"');
         $criteria->compare($lastactivity_sql, $this->lastactivity);
         $sort = new CSort;
         $sort->defaultOrder = array('name' => CSort::SORT_ASC);
         $sort->attributes = array(
             'name' => 'name',
             'email' => 'email',
             'status' => 'status',
             'createdon' => 'createdon',
             'lastactivity' => 'lastactivity',
         );
         $sort->applyOrder($criteria);
 
         return new CActiveDataProvider($this, array(
             'criteria' => $criteria,
             'sort' => $sort,
             'pagination' => array(
                 'pageSize' => Yii::app()->user->getState('contactPageSize', Yii::app()->params['RECORDPERPAGE_ADMIN']),
                 'currentPage' => Yii::app()->user->getState('Contact_page', 0),
             ),
         ));
     }
 CGRIDVIEW on display page
 ---------------------------
 <?php
         $this->widget('ext.selgridview.SelGridView', array(
             'id' => 'contact_grid',
             'dataProvider' => $dataProvider,
             'pageSizeVar' => 'contact',
             'columns' => array(
 		array(
                     'id' => 'autoId',
                     'class' => 'gridCheckBoxColumn',
                     'headerHtmlOptions' => array('class' => 'checkbox paracheck'),
                     'htmlOptions' => array('class' => 'checkbox paracheck'),
                 ),
                 array(
                     'header' => 'Last Activity',
                     'class' => 'gridDataColumn',
                     'name' => 'lastactivity',
                     'value' => 'CommonFunctions::formatDateTime($data->lastactivity)',
                     'htmlOptions' => array('class' => 'maincell'),
                     'headerHtmlOptions' => array('title' => Yii::t('app', 'LBL_LIST_SORT_DATE_TITLE'))
                 ),
             ),
         ));
         ?>
 
 
 Error
 ------
-Property "CSafeValidator.0" is not defined.
+CDbCommand failed to execute the SQL statement: SQLSTATE[42S22]: Column not found: 1054 Unknown column 't.lastactivity' in 'order clause'. The SQL statement executed was: SELECT t.*, (select max(date) from tbl_contact_action where contact_id=t.contact_id) as lastactivity FROM `tbl_contact` `t` WHERE t.status<>"Deleted" ORDER BY lastactivity, `t`.`lastactivity` LIMIT 10