Url parameter in magento 2 collection filter

Question

I need to filter Magento 2 custom grid model collection by URL parameter. I have used this below code.

protected function _initSelect() { 
 $objectManager = \Magento\Framework\App\ObjectManager::getInstance(); 
 $request = $objectManager->get('Magento\Framework\App\Request\Http'); 
 $seller_id = $request->getParam('seller_id');
 $this->addFilterToMap('increment_id', 'main_table.increment_id');
 $this->addFilterToMap('status', 'main_table.status');
 $this->addFilterToMap('seller_id', 'main_table.seller_id');
 $this->addFieldToFilter('seller_id', ['eq' => $seller_id]);
 $this->getSelect()->joinLeft(
 ['secondTable' => $this->getTable('sales_order_grid')], //2nd table name by which you want to join mail table
 'main_table.order_id = secondTable.entity_id', // common column which available in both table 
 '*' // '*' define that you want all column of 2nd table. if you want some particular column then you can define as ['column1','column2']
 )->group('main_table.order_id'); 
 //$this->addFieldToFilter('main_table.seller_id', ['eq' => '39']);
 parent::_initSelect();
 // var_dump($this->getSelect()->__toString());
 // exit;
 return $this; 
 }

When I log this seller_id it is showing by when I pass in filter not working. it is working when I pass a static value. I'm not sure how to filter a collection by param in the model.

Answer 1

parent::_initSelect(); should be called on start of _initSelect.

Code might look like:

 protected function _initSelect()
{
 parent::_initSelect();
 $tableDescription = $this->getConnection()->describeTable($this->getMainTable());
 foreach ($tableDescription as $columnInfo) {
 $this->addFilterToMap($columnInfo['COLUMN_NAME'], 'main_table.' . $columnInfo['COLUMN_NAME']);
 }
 $this->getSelect()->joinLeft(
 ['secondTable' => $this->getTable('sales_order_grid')], //2nd table name by which you want to join mail table
 'main_table.order_id = secondTable.entity_id', // common column which available in both table
 '*' // '*' define that you want all column of 2nd table. if you want some particular column then you can define as ['column1','column2']
 );
 $this->getSelect()->group('main_table.order_id');
 // Add your fiter after join
 return $this;
}