Question

Laravel通过折扣获得季节价格，并按价格ASC过滤产品。

我有这个季节表

+----+------------+------------+------------+-------+------+----------+------------+------------+------------+
| id | base_price | startDate  | endDate    | cost  | type | Duration | product_id | created_at | updated_at |
+----+------------+------------+------------+-------+------+----------+------------+------------+------------+
|  1 |     100.00 | 1537390800 | 1538773200 | 95.00 | day  |        2 |          9 | NULL       | NULL       |
|  2 |     100.00 | 1537390800 | 1538773200 | 85.00 | day  |        3 |          9 | NULL       | NULL       |
|  3 |     100.00 | 1537390800 | 1538773200 | 75.00 | day  |        4 |          9 | NULL       | NULL       |
|  4 |     100.00 | 1537390800 | 1538773200 | 70.00 | day  |        5 |          9 | NULL       | NULL       |
+----+------------+------------+------------+-------+------+----------+------------+------------+------------+

和产品表

+----+----------------------------+-----------+-----+-------+---------+--------------+---------------------+---------------------+---------------------+
| id | alias                      | status    | img | price | user_id | published_at | deleted_at          | created_at
 | updated_at          |
+----+----------------------------+-----------+-----+-------+---------+--------------+---------------------+---------------------+---------------------+
|  8 | toyota-corolla-1-6-elegant | draft     | 18  | 30    |       1 | 2018-08-14   | NULL                | 2018-08-14 15:06:12 | 2018-08-20 14:58:18 |
|  9 | test                       | published |     | 0     |       1 | 2018-08-23   | 2018-09-10 19:44:29 | 2018-08-23 14:45:18 | 2018-09-10 19:44:29 |
+----+----------------------------+-----------+-----+-------+---------+--------------+---------------------+---------------------+---------------------+

如您所见，我们有三个可能的选择

1）如果在选定的几天中没有季节表价格，则使用产品表中的价格

2）如果我们在base_price中有价格但没有价格但没有折扣我们使用base_price

3）如果我们选择2天（并进入日期范围），则在这种情况下我们使用字段成本95 $

我尝试了这段代码，但是在我需要以动态价格显示所有产品时，它只显示一种产品。

$products_obj->join('ec_season', function ($join) use($days) {
            $join->on( 'ec_products.id', '=', 'ec_season.product_id' )
                 ->where( 'ec_season.cost', DB::raw( "(
    select min(ec_season.cost)
    from ec_season
    where  `ec_season`.`product_id` = `ec_products`.`id`  and `ec_season`.`type` = 'day' and `Duration` <= '3'
)
" ) );
        });

我使用laravel 5.6。你能帮我吗？

我可以通过MySQL以最终成本（final_cost）创建新字段吗？并可以按final_cost

进行排序

编辑1

新代码，但仍返回重复的产品并显示 final_cost“ =>” ec_season.cost“ 而不是价格

$products_obj->leftJoin('ec_season', 'ec_season.product_id', '=', 'ec_products.id')         
                     ->select('*',
                DB::raw("COALESCE('ec_season.cost', 'ec_season.base_price', 'products.price') as final_cost"))
                                     ->where('ec_season.type', 'day')
                                     ->where('ec_season.Duration', '<=', 3)
                                     ->orderBy('final_cost', 'desc');

编辑2 或者更容易选择所有产品，并在按价格对该集合进行排序之后为每个正确的价格计算价格，并执行另一个sql请求，以指定的ID的顺序发出该请求。还是它会比用一个sql查询完成的所有过程慢？例如，如果我们有100种产品

Answer 1

像这样的事情可能会更好，但是不确定我是否满足了您的所有要求。也未经测试。

// use a left join to select all products, not just those with a related entry in the seasonal table
$products_obj->leftJoin('ec_season', 'ec_season.product_id', '=', 'ec_products.od')
    // maybe need to update the * to only select columns you need and prevent collisions
   // but just showing my idea which is to use COALESCE
    ->select('*', DB::raw("COALESCE('ec_season.cost', 'ec_season.base_price', 'products.price') as final_cost")
    ->where('ec_season.type', 'day')
    ->where('ec_season.Duration', '<=', 3)
    ->orderBy('final_cost', 'desc');

COALESCE MySQL Function

Laravel按季节价格过滤产品并有折扣

1 个答案: