如何用 migrate 创建 view table 视图？如何用原生 sql 语句创建表？

mysql里面有一种表叫做视图是一张通过查询语句生成的虚拟表。项目中有个排行榜的需求，需要通过mysql统计用户积分的排行，视图表的建表语句如下：

CREATE VIEW `rankings` AS select `t1`.`customer_id` AS `customer_id`,
`t1`.`total_score` AS `total_score`,
count(0) AS `ranking_num` from (`score_accounts` `t1` left join `score_accounts` `t2` 
    on(((`t2`.`total_score` > `t1`.`total_score`) or ((`t2`.`total_score` = `t1`.`total_score`) 
        and (`t2`.`customer_id` >= `t1`.`customer_id`))))) 
group by `t1`.`total_score`,`t1`.`customer_id`;

但是如何同使用migration，因为按照常规建的migrate建表方式，不好写？我们能不能直接用sql语句建表呢？
答案是可以通过查询构造器来达到。
引入：use Illuminate\Support\Facades\DB;
执行：DB::statement( );
代码如下：

<?php

use Illuminate\Support\Facades\Schema;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Database\Migrations\Migration;
use Illuminate\Support\Facades\DB;

class CreateRankingsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {

        //查询构造器建表：
        DB::statement( 'CREATE VIEW `rankings` AS select `t1`.`customer_id` AS `customer_id`,
`t1`.`total_score` AS `total_score`,
count(0) AS `ranking_num` from (`score_accounts` `t1` left join `score_accounts` `t2` 
    on(((`t2`.`total_score` > `t1`.`total_score`) or ((`t2`.`total_score` = `t1`.`total_score`) 
        and (`t2`.`customer_id` >= `t1`.`customer_id`))))) 
group by `t1`.`total_score`,`t1`.`customer_id`;
     ' );
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('rankings');
    }
}