Laravel - 如果查询为空，则返回不同的查询

Question

我编写的查询可能在某些时候包含为空的列，这会导致查询返回一个空数组，即使活动表中有一个值。这是因为如果列值为空，则查询无法生成join。我正在尝试编写一个if 语句来返回campaign，即使它的值为空但它仍然返回一个空数组。如果我在 if 语句中运行查询，它会返回我正在寻找的内容，我只是无法触发 if 语句。

  public function getCampaigns(Request $request)
  {
    $authUser = auth()->user();
    $business = $authUser['business_id'];
    $query = campaigns::join('offers', 'campaigns.offer_id', '=', 'offers.id')
            ->join('conditionals', 'campaigns.conditional_id', '=', 'conditionals.id')
            ->join('triggers', 'campaigns.offer_id', '=', 'triggers.id')
            ->select('campaigns.*',
            'triggers.name AS trigger_name',
            'offers.name AS offer_name',
            'offers.reward_amount as offer_reward_amount',
            'offers.plaid_category_id as offer_plaid_id',
            'conditionals.dollars_min',
            'conditionals.dollars_max',
            'conditionals.dollars_more',
            'conditionals.xDays as days_since_last_purchase',
            'conditionals.xDate as date_since_last_purchase',
            'conditionals.xPercent as percentage_more',
            'conditionals.xPurchases as purchases_x_times',
            'conditionals.start_date',
            'conditionals.end_date',
            'conditionals.plaid_category_id')
            // ->whereNull('campaigns.trigger_id', 'campaigns.offer_id', 'campaigns.conditional_id')
            ->where('campaigns.business_id', '=', $business);
    if ($query->count() === 0){
      $query = campaigns::select('*')->where('business_id', '=', $business);
    }
    return $query->get();
  }

Answer 1

查询构建器get()方法如果没有找到结果不会返回null，它会返回一个空集合。

改为检查空集合：

if ($query->count() === 0){

我也建议重命名 $query 以提高可读性，因为它没有分配查询，而是分配了结果。