Php 在laravel querybuilder中使用join关键字时，如何添加字段？

我想添加sellamount和buyamount。我尝试了以下代码段，但它显示了错误。有人能帮忙吗

DB::table('tbl_buyer')
->select('buyer','tbl_seller.seller','buyamount','tbl_seller.sellamount',
'buyamount + sellamount')
->join('tbl_seller','tbl_seller.seller','=','tbl_buyer.buyer')
->get();

试试这个-

DB::table('tbl_buyer')
->select('buyer','tbl_seller.seller','buyamount','tbl_seller.sellamount','(buyamount + tbl_seller.sellamount) as total')
->join('tbl_seller','tbl_seller.seller','=','tbl_buyer.buyer')
->get();

谢谢大家的帮助。 这对我有用

DB::table('tbl_buyer')
->select(\DB::raw('buyer,tbl_seller.seller,buyamount,tbl_seller.sellamount, buyamount + tbl_seller.sellamount as total '))
->join('tbl_seller','tbl_seller.seller','=','tbl_buyer.buyer')
->orderBy('total','Desc')
->limit(5)
->get();

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请用一些示例数据解释您获得的错误：BL_买方买方买方买方买方买方买方买方买方买方买方买方买方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方买方买方买方买方买方买方买方买方买方买方买方买方买方买方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方卖方。SQLSTATE[42S22]：未找到列：“字段列表”中的1054未知列“buyamount+tbl_seller.sellamount”