如何创建视图(producer_view和retailer_view),显示当它们是供应商和客户时每笔交易的总金额SUM( unit_price * quantity )
?
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:
每个事务的
supplier_id
和client_id
存储在两个多态关联中,其中supplier_type
和client_type
可以是App\Producer
或App\Retailer
。每个事务的
unit_price
和quantity
存储在子表中。两个父表是:
Producer
+----+------+
| id | name |
+----+------+
| 1 | foo |
| 2 | bar |
+----+------+
Retailer
+----+------+
| id | name |
+----+------+
| 1 | baz |
| 2 | qux |
+----+------+
在交易中,生产商和零售商可以是供应商或客户。
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 |
+----+---------+-------------+---------------+-----------+--------------+
每个事务的详细信息记录在项目表中:
Item
+----+----------------+------------+----------+
| id | transaction_id | unit_price | quantity |
+----+----------------+------------+----------+
| 1 | 1 | 10 | 1 |
| 2 | 1 | 20 | 1 |
| 3 | 2 | 30 | 1 |
| 4 | 2 | 40 | 1 |
| 5 | 3 | 50 | 1 |
| 6 | 3 | 60 | 1 |
| 7 | 4 | 70 | 1 |
| 8 | 4 | 80 | 1 |
| 9 | 5 | 2 | 2 |
| 10 | 6 | 3 | 3 |
| 11 | 7 | 4 | 4 |
| 12 | 8 | 5 | 5 |
+----+----------------+------------+----------+
SQLFiddle来自下面的验证答案:
producer_view
retailer_view
最佳答案
尝试以下查询:
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
关于mysql - MySQL View :多态关联和子表,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/49539899/