我需要两个不同表中两个不同列的总和，即 tbl_bill 以及 tbl_receipt .
待确认收据

id receipt_no  member_id   receipt_amount
 1  21001         21        20500
 2  21002         21        200

tbl\U成员

id    name
  21    priya

待定发票

id bill_no  order_id   member_id     bill_value
 1  30001       30          21          20928
 2  0002501     25          21          12030

我要这样回答

member_id  member_name  receipt_sum  bill_sum   
21         priya        20700         32958

我试着做左连接，但它的总和增加了一倍。有人能帮我吗？

$adapter = $this->tableGateway->getAdapter();
       $orderTable = new TableGateway('tbl_receipt', $adapter);
       $sqlSelect = $orderTable->getSql()->select();
       $sqlSelect->columns(array('id'=>'id','bill_amount'=>'bill_total','sum_receipt_amount'=>new \Zend\Db\Sql\Expression('SUM(tbl_receipt.receipt_amount)'))); 
       $sqlSelect->join('tbl_member','tbl_member.id = tbl_receipt.member_id', array('member_id'=>'id','member_name'=>'name'),'LEFT');
     //  $sqlSelect->join('tbl_receipt','tbl_receipt.member_id = tbl_bill.member_id', array('receipt_id'=>new \Zend\Db\Sql\Expression('(tbl_receipt.receipt_amount)')),'LEFT');

       $sqlSelect->group('tbl_member.id');
       $resultSet = $orderTable->selectWith($sqlSelect);
        //echo"<pre>";

   // print_r($resultSet); die;
  return $resultSet;