Laravel database seeding from old tables

You can use multiple database connections in laravel to connect to both databases.

config/database.php

return [
    'connections' => [
        'old_db' => [
            'driver'    => 'mysql',
            'host'      => env('DB_HOST_OLD'),
            'database'  => env('DB_DATABASE_OLD'),
            'username'  => env('DB_USERNAME_OLD'),
            'password'  => env('DB_PASSWORD_OLD'),
        ],
        'new_db' => [
            'driver'    => 'mysql',
            'host'      => env('DB_HOST'),
            'database'  => env('DB_DATABASE'),
            'username'  => env('DB_USERNAME'),
            'password'  => env('DB_PASSWORD'),
        ],
    ],
];

Then in your seed file you can connect to your old database and loop through those items and insert them in your new database

UserTableSeeder.php

$users = DB::connection('old_db')->table('users')->get();

foreach($users as $user){
    DB::connection('new_db')->table('users')->insert([
        'name' => $user->username, //different fieldnames
        'email' => $user->emailaddress, //different fieldnames
    ]);  
}

If I were You and I needed FAST one time solution, I would:

Get data from old table using DB facade:

 $rows = DB::table('users')->get();    

Structure my foreach something, which works in database seeder and echo it:

foreach ($rows as $row) {
  echo("DB::table('table')->insert(array(
    'name' => '$row->name',
    'email' => '$row->email'
  ));
  <br />");
}

Copy&paste it into database seeder and run it OR structure statemens below to work directly in MySQL and run it in MySQL. It looks stupid, but very fast and works.

Code lines above aren't tested, written from memory.