Get specific columns from Left Join

Question

I am trying to join two tables like below

    $objectManager =  \Magento\Framework\App\ObjectManager::getInstance();

    $collection = $objectManager->get('Advance\Module\Model\Method')
    ->getCollection()->addFieldToFilter('stores', ['finset' => $store_id]);

    $collection->getSelect()->joinLeft( ['shippingrate'=> 'shippingrate'], 
    'shippingrate.method_id = main_table.method_id', ['main_table.method_id']);

This is returning all data from two tables. I could not get specific columns from the end result.

Answer 1

You can refer to this example of mine:

protected function filterOrder($payment_method)
    {
        $this->sales_order_table = ""main_table"";
        $this->sales_order_payment_table = $this->getTable(""sales_order_payment"");
        $this->getSelect()
            ->join(array('payment' =>$this->sales_order_payment_table), $this->sales_order_table . '.entity_id= payment.parent_id',
                array('payment_method' => 'payment.method',
                    'order_id' => $this->sales_order_table.'.entity_id'
                )
            );
        $this->getSelect()->where(""payment_method="".$payment_method);
    }