ProductManageController.php

public function deleteStokAwal(Request $req)
    {
        if($req->stok_delete){
            $product = Product::where('kode_barang', $req->kode_barang)->first();
            $jumlahStok = ($req->stok_besar*$product->pack) + $req->stok_kecil;
            $product->stok -= $jumlahStok;
            if($product->stok < 0){
                Session::flash('update_failed', 'Stok Kurang Dari 0');
                return back();
            }
            $product->save();
        }

        if(DB::table('stok_awal')->where('kode_barang', $req->kode_barang)->first()){
            DB::table('stok_awal')->where('kode_barang', $req->kode_barang)
                                ->update([
                                    'jumlah_besar' => 0,
                                    'jumlah_kecil' => 0
                                ]);
        }
        return back();
    }