Laravel雄辩地使用null作为select值的列值？

Question

如何在Laravel eloquent中使用null作为列值,如下面的查询(以下查询不起作用,以及它的示例).

$query = \DB::table('invoices as inv')
        ->leftjoin('customer as c', 'c.id', '=', 'inv.customer_id')
        ->select([
            'inv.id',
            'inv.invoice_date',
            'inv.invoice_no',
            'null as voucher_no',
            'null as credit',
        ]);

在这里,' null as voucher_no '不起作用.如何在此查询中使用null.

Answer 1

DB::raw在列周围使用,这将强制laravel按原样传递列名:

$query = \DB::table('invoices as inv')
    ->leftjoin('customer as c', 'c.id', '=', 'inv.customer_id')
    ->select([
        'inv.id',
        'inv.invoice_date',
        'inv.invoice_no',
        DB::raw('null as voucher_no'),
        DB::raw('null as credit'),
    ]);