isset 中的非法偏移类型或为空 Laravel

Illegal offset type in isset or empty Laravel

我使用以下查询获取 Laravel 中特定 Table 的项目 ID 和 ID。

$projectlist = Projects::Where('customer',$request->input('client_name'))->pluck(DB::raw("CONCAT('project_prefix','project_nos') AS projectid"),"id");

我遇到以下错误。

message Illegal offset type in isset or empty
exception   ErrorException
file    /var/www/msstone/vendor/laravel/framework/src/Illuminate/Support/Str.php

项目模型

namespace App;

use Illuminate\Database\Eloquent\Model;

class Projects extends Model
{
    protected $guarded = ['id'];

    protected $table = 'projects';

}

尝试更改 eloquent 查询:

$projectlist=Projects::Where('customer',$request->input('client_name'))->pluck(DB::raw("CONCAT('project_prefix','project_nos') AS projectid"),"id");

$projectlist = Projects::select(DB::raw("CONCAT(project_prefix,project_nos) AS projectid"),'id')->where('customer',$request->input('client_name'))->pluck("projectid","id");