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(\'leg

Answer 1

None of these answers worked for me. I created my own function based on @deyes answer.

private static function chunk($query, $max, $function) {
    $counter = preg_replace('/SELECT (.*?) FROM/', 'SELECT COUNT(*) FROM', $query);
    $total = DB::connection('legacy')->select($counter)[0];
    $total = (array)$total;
    $total = $total['COUNT(*)'];

    $pages = ceil($total / $max);

    for ($i = 1; $i < ($pages + 1); $i++) {
        $offset = (($i - 1)  * $max);
        $start = ($offset == 0 ? 0 : ($offset + 1));
        $items = DB::connection('legacy')->select($query . ' LIMIT ' . $offset . ', ' . $max);

        $function($items);

        unset($items);
    }
}

Usage

YourClass::chunk('SELECT * FROM tablename', 50, function($items) {
    //Work with $items.
});

Please note that this a simple quick fix and your query probably has to be fairly simple as I'm using search-replace to build a count query and I'm just tacking on LIMIT X, Y to the end of the query but it works for me.