title: Laravel ,Column already exists :1060 Duplicate column name
body: <h2><strong>I am running laravel version 5.4.22</strong></h2>
  
  <p>I use <code>php artisan migrate:rollback</code> in terminal then error message bellow </p>
  
  <blockquote>
    <p>H:\wamp_server\www\cms>php artisan migrate:rollback</p>
    
    <p>[Illuminate\Database\QueryException]   SQLSTATE[42S21]: Column
    already exists: 1060 Duplicate column name 'is_admin' (SQL: alter
    table <code>posts</code> add <code>is_admin</code> int not null)</p>
    
    <p>[PDOException]   SQLSTATE[42S21]: Column already exists: 1060
    Duplicate column name 'is_admin'</p>
  </blockquote>
  
  <p>migration code below</p>
  
  <pre><code>    &lt;?php
  
  use Illuminate\Support\Facades\Schema;
  use Illuminate\Database\Schema\Blueprint;
  use Illuminate\Database\Migrations\Migration;
  
  class AddIsAdminColumnToPostsTable extends Migration
  {
      /**
       * Run the migrations.
       *
       * @return void
       */
      public function up()
      {
          Schema::table('posts', function (Blueprint $table) {
              //
              $table-&gt;integer('is_admin')-&gt;unsigned();
  
          });
      }
  
      /**
       * Reverse the migrations.
       *
       * @return void
       */
      public function down()
      {
          Schema::table('posts', function (Blueprint $table) {
              //
  
              $table-&gt;integer('is_admin');
          });
      }
  }
  </code></pre>