How to chunk results from a custom query in Laravel

Question

I have a custom query that grabs data from the old system and maps it to models in the new system. The query looks like this:

$companies = DB::connection('legacy')->select("...");

And since it's a lot of data, I'd like to use Eloquent's chunk feature (just sample code copied from their docs):

User::chunk(200, function($users)
{
    foreach ($users as $user)
    {
        //
    }
});

How do I implement this?

---

Edit: My code now looks like this, which results in no response:

DB::connection('legacy')->select("SELECT * FROM companies")->chunk(200, function($companies) {
    foreach ($companies as $company) {
        // dd($company);
        $entity       = Entity::firstOrNew(['external_id' => $company->companyKey]);
        $entity->name = $company->companyName;
        $entity->save();
    }
});

Answer 1

The chunk feature is only available for Eloquent models and QueryBuilder requests, e.g.

DB::table('tbl')->where('num', '>', 3)->chunk(500, function($rows) {
    // process $rows
});

But it won't work for DB::select('...') request. You need to either use a QueryBuilder request, or use an underlying PDO object to query the database, e.g:

$pdo = DB::getPdo();
$sth = $pdo->prepare("SELECT ....");
$sth->execute();
while ($row = $sth->fetch(PDO::FETCH_ASSOC))
{
    // ...
}