如何将此sql查询转换为laravel查询生成器

Question

选择t.product_id，t.on_hand，t.created_at 来自table t， （SELECT MAX（purchase_id）为pId FROM table Group by product_id）tg 其中t.purchase_id = tg.pId

Answer 1

$result = DB::table('table as t')
->select('t.product_id', 't.on_hand', 't.created_at')
->join(DB::raw('(SELECT MAX(purchase_id) as pId FROM table Group by product_id) tg'), function($join) {
    $join->on('t.purchase_id', '=', 'tg.pId');
})->get();