how to insert comasepereated value in laravel eloquent code example

Example 1: laravel find query

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Flight extends Model
{
    /**
     * The primary key associated with the table.
     *
     * @var string
     */
    protected $primaryKey = 'flight_id';
}

Example 2: laravel find query

$model = App\Models\Flight::where('legs', '>', 100)
            ->firstOr(['id', 'legs'], function () {
                // ...
            });