Cgridview With Csqldataprovider Update

I am using a CGridView to search over multiple tables in my database and display results, the search criteria is built using a from that is sent using GET. This works fine until there is an ajax update either for the sorting or I have a dropdown list for pagination which also updates the CGridView via ajax.

The error and trace I recieve is:

Error 500: <h1>PHP Error [8]</h1>
<p>Undefined index: categoryId (/home/stephen/www/wrap_crcpd_staging/protected/models/Product.php:98)</p>
<pre>#0 /home/stephen/www/wrap_crcpd_staging/protected/models/Product.php(98): CWebApplication->handleError()
#1 /home/stephen/www/wrap_crcpd_staging/protected/views/product/index.php(47): Product->SqlSearch()
#2 /home/stephen/www/wrap_crcpd_staging/framework/web/CBaseController.php(126): require()
#3 /home/stephen/www/wrap_crcpd_staging/framework/web/CBaseController.php(95): ProductController->renderInternal()
#4 /home/stephen/www/wrap_crcpd_staging/framework/web/CController.php(869): ProductController->renderFile()
#5 /home/stephen/www/wrap_crcpd_staging/framework/web/CController.php(782): ProductController->renderPartial()
#6 /home/stephen/www/wrap_crcpd_staging/protected/controllers/ProductController.php(685): ProductController->render()
#7 /home/stephen/www/wrap_crcpd_staging/framework/web/actions/CInlineAction.php(49): ProductController->actionIndex()
#8 /home/stephen/www/wrap_crcpd_staging/framework/web/CController.php(308): CInlineAction->runWithParams()
#9 /home/stephen/www/wrap_crcpd_staging/framework/web/filters/CFilterChain.php(133): ProductController->runAction()
#10 /home/stephen/www/wrap_crcpd_staging/framework/web/filters/CFilter.php(40): CFilterChain->run()
#11 /home/stephen/www/wrap_crcpd_staging/framework/web/CController.php(1145): CAccessControlFilter->filter()
#12 /home/stephen/www/wrap_crcpd_staging/framework/web/filters/CInlineFilter.php(58): ProductController->filterAccessControl()
#13 /home/stephen/www/wrap_crcpd_staging/framework/web/filters/CFilterChain.php(130): CInlineFilter->filter()
#14 /home/stephen/www/wrap_crcpd_staging/framework/web/CController.php(291): CFilterChain->run()
#15 /home/stephen/www/wrap_crcpd_staging/framework/web/CController.php(265): ProductController->runActionWithFilters()
#16 /home/stephen/www/wrap_crcpd_staging/framework/web/CWebApplication.php(282): ProductController->run()
#17 /home/stephen/www/wrap_crcpd_staging/framework/web/CWebApplication.php(141): CWebApplication->runController()
#18 /home/stephen/www/wrap_crcpd_staging/framework/base/CApplication.php(169): CWebApplication->processRequest()
#19 /home/stephen/www/wrap_crcpd_staging/index.php(13): CWebApplication->run()
</pre>

categoryId is a GET variable which is not inserted into the ajax requests.

So how can overcome this problem?

The search code that returns the CSqlDataProvider is:

 public function SqlSearch(){
//            search fields from $_GET to build WHERE clause   
            
            $joint_m_s = "";
            $joint_m_e = "";
            $joint_a_e = "";
            $joint_a_s = "";
            $joint_c_e = "";
            $joint_c_s = "";
            echo Yii::trace(CVarDumper::dumpAsString($_GET), 'vardump');
            if(!isset($_GET['Product'])){   //search has not been entered
                $where = "1 ";
            }else {
                
                $where = "";
                $join = "";
                if($_GET['Product']['categoryId'] != ''){
                    if($_GET['Product'][$_GET['Product']['categoryId']]['productSubCategoryId_check'] == 1 ){ 
                        $where .= $join."p.productSubCategoryId = ".$_GET['Product'][$_GET['Product']['categoryId']]['productSubCategoryId'];
                        $join = " AND ";
                    } 
                }
                
                if( $_GET['company_check'] == 1 ){ 
                    $where .= $join."p.companyId = ".$_GET['Company']['name'];
                    $join = " AND ";
                } 
                if( $_GET['percentRecycledContent_check'] == 1 ){ 
                    $where .= $join."p.percentRecycledContent BETWEEN ".$_GET['Product']['percentRecycledContent']['start']." AND ".$_GET['Product']['percentRecycledContent']['end'];
                    $join = " AND ";
                } 
                if( $_GET['manufactured_check'] == 1 ){ 
                    $where .= $join."pm.manufactureId = ".$_GET['Manufactured']['name'];
                    $join = " AND ";
                    $joint_m_s = "(";
                    $joint_m_e = ") LEFT JOIN productmanufacture AS pm ON p.id = pm.productId";
                } 
                if( $_GET['availability_check'] == 1 ){ 
                    $where .= $join."pa.availabilityId = ".$_GET['Availability']['name'];
                    $join = " AND ";
                    $joint_a_s = "(";
                    $joint_a_e = ") LEFT JOIN productavailability AS pa ON p.id = pa.productId";
                } 
                if( $_GET['credential_check'] == 1){
                    
                    foreach($_GET['Credential'] as $id => $credential){
                        
                        if(isset($credential['id']) && $credential['id'] > 0){
                            $where .= $join."pc.credentialId = ".$id;
                            $join = " AND ";
                        }
                    }
                    
                    $joint_c_s = "(";
                    $joint_c_e = ") LEFT JOIN productcredentials AS pc ON p.id = pc.productId";
                }
                if($_GET['Product']['Name'] != ''){
                    if(strpos($_GET['Product']['Name'], ',')){
                        $where .= " OR (";
                        $join = "";
                        $search = explode(',', $_GET['Product']['Name']);
                        foreach($search as $s){
                            $where .= $join."p.Name LIKE '%".trim($s)."%'";
                            $join = " OR ";
                        }
                        $where .= ")";
                    }elseif(strpos($_GET['Product']['Name'], " ")){
                        $where .= " OR (";
                        $join = "";
                        $search = explode(" ", $_GET['Product']['Name']);
                        foreach($search as $s){
                            $where .= $join."p.Name LIKE '%".trim($s)."%'";
                            $join = " OR ";
                        }
                        $where .= ")";
                    }else{
                        $where .= $join."p.Name LIKE '%".trim($_GET['Product']['Name'])."%'";
                    }
                    $join = " AND ";
                }
                if($_GET['Product']['categoryId'] != ''){
                    $where .= $join."p.categoryId = ".$_GET['Product']['categoryId'];
                }
                if($where == ''){
                    $where = "1";
                }
            }
            
            $sql = "SELECT p.id, category.name AS categoryName, subCategory.name AS subCategoryName, p.Name, company.name AS companyName, p.percentRecycledContent FROM ".$joint_m_s.$joint_a_s.$joint_c_s."((product AS p LEFT JOIN company AS company ON p.companyId = company.id) LEFT JOIN productcategory AS category ON p.categoryId = category.id) LEFT JOIN productcategory AS subCategory ON p.productSubCategoryId = subCategory.id ".$joint_m_e.$joint_a_e.$joint_c_e." WHERE ".$where." GROUP BY p.id";
            $count_sql = "SELECT COUNT(p.id) FROM ".$joint_m_s.$joint_a_s.$joint_c_s."product AS p ".$joint_m_e.$joint_a_e.$joint_c_e." WHERE ".$where;
            $count = Yii::app()->db->createCommand($count_sql)->queryScalar();
            return new CSqlDataProvider($sql, array(
                        'totalItemCount'=>$count,
                        'sort'=>array(
                            'attributes'=>array(
                                'categoryName'=>array(
                                    'asc'=>'category.name',
                                    'desc'=>'category.name DESC',
                                ),
                                'subCategoryName'=>array(
                                    'asc'=>'subCat.name',
                                    'desc'=>'subCat.name DESC',
                                ),
                                'Name'=>array(
                                    'asc'=>'p.Name',
                                    'desc'=>'p.Name DESC',
                                ),
                                'companyName'=>array(
                                    'asc'=>'company.name',
                                    'desc'=>'company.name DESC',
                                ),
                                'percentRecycledContent'=>array(
                                    'asc'=>'p.percentRecycledContent',
                                    'desc'=>'p.percentRecycledContent DESC',
                                ),
                            ),
                        ),
                        'pagination'=>array(
                                'pageSize'=> Yii::app()->user->getState('pageSize',Yii::app()->params['defaultPageSize']),
                        ),

		));
        }

The CGridView code is:

$this->widget('zii.widgets.grid.CGridView', array(
	'dataProvider' => $model->SqlSearch(),
        'id' => 'product-grid',
        'template' => '{items}{pager}',
        'emptyText' => 'No products found',
        'ajaxUrl' => $_SERVER['QUERY_STRING'],
        'pager'=>array(
            'header'         => '',
            'prevPageLabel'  => '',
            'nextPageLabel'  => '',
        ), 
	'columns' => array(
                array(
                    'header' => 'Category',
                    'name' => 'categoryName',
                    'value' => '$data["categoryName"]',
                ),
                array(
                    'header' => 'Sub-category',
                    'name' => 'SubCategoryName',
                    'value' => '$data["subCategoryName"]',
                ),
                array(
                    'header' => 'Product',
                    'labelExpression' => '$data["Name"]',
                    'class' => 'CLinkColumn',
                    'urlExpression' => 'Yii::app()->createUrl("product/view", array("id"=>$data["id"]))',
                ),
		array(
                    'header' => 'Supplier',
                    'name' => 'companyName',
                    'value' => '$data["companyName"]',
                ),
                array(
                    'header' => '% recycled',
                    'name' => 'percentRecycledContent',
                    'value' => '$data["percentRecycledContent"]',
                ),
                array(
                    'class' => 'CLinkColumn',
                    'header' => 'Wishlist',
                    //'labelExpression' => '',
                    //'urlExpression' => '',
                    
                ),
            )
)); 

Thank you