在具有特定条件的 VIEW SQL 上从三个表中加入和求和答案

【问题标题】：JOIN and SUM from Three Table on VIEW SQL with specific criteria在具有特定条件的 VIEW SQL 上从三个表中加入和求和
【发布时间】：2016-09-07 10:35:31
【问题描述】：

我在 mysql 上创建视图时遇到了问题。我有 3 张桌子：

价格表

+----------+-----------+
| id_price | price_name|
+----------+-----------+
| 11       | retail    |
| 12       | agen      |
| 13       | subagen   | 
| 14       | distro    | 
+----------+-----------+

基本价格

+------------+-------------+
| id_product | basic_price |
+------------+-------------+
| 1001       | 1000        |
| 1002       | 2000        |
| 1003       | 3000        |
| 1004       | 4000        |
+------------+-------------+

保证金价格

+----------+------------+-------------+
| id_price | id_product | margin_price|
+----------+------------+-------------+
| 11       | 1001       | 100         |
| 12       | 1001       | 200         |
| 13       | 1001       | 300         |
| 14       | 1001       | 400         |
| 11       | 1002       | 200         |
| 12       | 1002       | 300         |
| 13       | 1002       | 400         |
| 14       | 1002       | 500         |
| 11       | 1003       | 300         | 
| 12       | 1003       | 400         |
| 13       | 1003       | 500         |
| 14       | 1003       | 600         |
| 11       | 1004       | 400         | 
| 12       | 1004       | 500         |
| 13       | 1004       | 600         |
| 14       | 1004       | 700         |
+----------+------------+-------------+

现在，我想对 basic_price 列和 margin_price 列进行 VIEW 和 SUM，如下所示：

+----------+-----------+------------+----------+-------------+------------+
|id_product|basic_price|retail_price|agen_price|subagen_price|distro_price|
+----------+-----------+------------+----------+-------------+------------+
| 1001     | 1000      | 1100       | 1200     | 1300        | 1400       |
| 1002     | 2000      | 2200       | 2300     | 2400        | 2500       |
| 1003     | 3000      | 3300       | 3400     | 3500        | 3600       |
| 1004     | 4000      | 4400       | 4500     | 4600        | 4700       |
+----------+-----------+------------+----------+-------------+------------+

我该怎么办，你能给出这个问题的代码解决方案吗？

【问题讨论】：

在哪里可以买到retail_price,agen_price,subagen_price,distro_price？

标签： mysql sql join sum sql-view

【解决方案1】：

select
  bp.id_product,
  bp.basic_price,
  SUM(CASE
      WHEN pl.price_name='retail' THEN mp.margin_price ELSE 0 
      END) as retail_price
  SUM(CASE
      WHEN pl.price_name='agen' THEN mp.margin_price ELSE 0 
      END) as agen_price,
  SUM(CASE
      WHEN pl.price_name='subagen' THEN mp.margin_price ELSE 0 
      END) as subagen_price,
  SUM(CASE
      WHEN pl.price_name='distro' THEN mp.margin_price ELSE 0 
      END) as distro_price
from basic_price bp
   join margin_price mp on bp.id_product=mp.id_product
   join price_list pl on mp.id_price =pl.id_price 
GROUP by bp.id_product

【讨论】：

【解决方案2】：

  SELECT 
    A.id_product, 
    A.basic_price, 
    SUM(CASE WHEN C.id_price = 11 THEN A.basic_price + B.margin_price ELSE 0 END) AS retail_price,
    SUM(CASE WHEN C.id_price = 12 THEN A.basic_price + B.margin_price ELSE 0 END) AS agen_price,
    SUM(CASE WHEN C.id_price = 13 THEN A.basic_price + B.margin_price ELSE 0 END) AS subagen_price,
    SUM(CASE WHEN C.id_price = 14 THEN A.basic_price + B.margin_price ELSE 0 END) AS distro_price
  FROM basic_price A 
    JOIN margin_price B ON A.id_product = B.id_product 
    JOIN price_list C ON C.id_price = B.id_price
  GROUP BY A.id_product, A.basic_price

【讨论】：