Question

如何创建视图（ producer_view 和 retailer_view ），以显示每个交易 SUM( unit_price * quantity ) 时的总金额>供应商和客户？

producer_view
+------+-------------------+-----------------+
| name | as_supplier_total | as_client_total |
+------+-------------------+-----------------+
| foo  |               144 |               9 |
| bar  |                 9 |             264 |
+------+-------------------+-----------------+

retailer_view
+------+-------------------+-----------------+
| name | as_supplier_total | as_client_total |
+------+-------------------+-----------------+
| baz  |                16 |             125 |
| qux  |               245 |              16 |
+------+-------------------+-----------------+

我的两个困难是：

每个交易的supplier_id和client_id 存储在两个多态关联中supplier_type和{ {1}}可以是client_type或App\Producer。
每个交易的App\Retailer和unit_price 都存储在子表中。

两个父表是：

quantity

在交易中，生产商和零售商可以是供应商或客户强>

Producer
+----+------+
| id | name |      
+----+------+
|  1 | foo  |     
|  2 | bar  |      
+----+------+

Retailer
+----+------+
| id | name |
+----+------+
|  1 | baz  |
|  2 | qux  |
+----+------+

每个交易的详细信息记录在项表中：

Transaction
+----+---------+-------------+---------------+-----------+--------------+
| id | product | supplier_id | supplier_type | client_id |  client_type |
+----+---------+-------------+---------------+-----------+--------------+
|  1 | a       |           1 |  App\Producer |         1 | App\Retailer |
|  2 | b       |           2 |  App\Retailer |         1 | App\Retailer |
|  3 | c       |           1 |  App\Producer |         2 | App\Producer |
|  4 | d       |           2 |  App\Retailer |         2 | App\Producer |
+----+---------+-------------+---------------+-----------+--------------+

来自下面验证答案的SQLFiddle：

Answer 1

尝试以下查询：

对于制作人：

SELECT
  p.name,
  SUM(i.quantity * i.unit_price) AS as_supplier_total,
  cagg.as_client_total
FROM producer p
LEFT JOIN transaction t on t.supplier_id = p.id AND t.supplier_type = 'App\\Producer'
LEFT JOIN item i ON t.id = i.transaction_id
LEFT JOIN (
  SELECT
    p.id,
    SUM(i.quantity * i.unit_price) AS as_client_total
  FROM producer p
  LEFT JOIN transaction t on t.client_id = p.id AND t.client_type = 'App\\Producer'
  LEFT JOIN item i ON t.id = i.transaction_id
  GROUP BY p.id
) AS cagg ON cagg.id = p.id
GROUP BY p.id

对于零售商：

SELECT
  r.name,
  SUM(i.quantity * i.unit_price) AS as_supplier_total,
  cagg.as_client_total
FROM retailer r
LEFT JOIN transaction t on t.supplier_id = r.id AND t.supplier_type = 'App\\Retailer'
LEFT JOIN item i ON t.id = i.transaction_id
LEFT JOIN (
  SELECT
    r.id,
    SUM(i.quantity * i.unit_price) AS as_client_total
  FROM retailer r
  LEFT JOIN transaction t on t.client_id = r.id AND t.client_type = 'App\\Retailer'
  LEFT JOIN item i ON t.id = i.transaction_id
  GROUP BY r.id
) AS cagg ON cagg.id = r.id
GROUP BY r.id

MySQL视图：多态关联和子表

1 个答案: