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) as 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();