使用 Peewee ORM 显示连接数据答案

【问题标题】：Display joined data with Peewee ORM使用 Peewee ORM 显示连接数据
【发布时间】：2018-05-28 08:59:59
【问题描述】：

使用 PeeWee Orm 我创建了两个表（我已经删除了很多与此查询无关的字段）

产品表

class Product(BaseModel):
    fm_price = FloatField(null=True)
    magento = IntegerField(db_column='magento_id', null=True, index=True)
    sku = CharField(index=True, null=True, unique=True)
    # Compare these two fields to on or offline products
    magento_status_fm = IntegerField(null=True)
    magento_status_ff = IntegerField(null=True)
    # Date fields to put error dates in
    ff_price_error = DateField(index=True, null=True)
    ff_stock_error = DateField(index=True, null=True)
    fm_price_error = DateField(index=True, null=True)
    fm_stock_error = DateField(index=True, null=True)
    ff_check_date = DateField(null=True, index=True)  # When did we get this product from FF

    class Meta:
        db_table = 'products'
        indexes = (
            (('fm_price', 'vip_price', 'education_price'), False),
        )

价格表

class Price(BaseModel):
    price_pk = PrimaryKeyField()
    entity_id = ForeignKeyField(Product, to_field='magento', null=True, on_update='CASCADE', on_delete='CASCADE')
    customer_group_id = IntegerField(null=True)
    final_price = FloatField(null=True)
    min_price = FloatField(null=True)
    check_date = DateField(null=True)

    class Meta:
        indexes = (
            (('entity_id', 'customer_group_id'), True),
        )

示例内容：

产品：

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------    ------------------------------------------------------------------------------
| id | CREATION            | MODIFICATION        | fm_price | fm_stock | vip_price | education_price | magento_id | omit | sku             | url                  | web_stock | magento_status_fm | magento_status_ff | ff_price_error | ff_stock_error |     fm_price_error | fm_stock_error | fm_vip_price_error | ff_vip_price_error | ff_check_date |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------    ------------------------------------------------------------------------------
| 3  | 2017-12-12 12:53:01 | 2017-12-14 09:31:44 | 109      | NULL     | NULL      | NULL            | 15212      | NULL | epiea10nach1    | https://www.absolut… | NULL      | NULL              | 1                 | NULL           | NULL           | NULL               | NULL           | NULL               | NULL               | 2017-12-14    |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------    ------------------------------------------------------------------------------
| 5  | 2017-12-12 12:53:01 | 2017-12-14 09:31:44 | 545      | NULL     | NULL      | NULL            | 15433      | NULL | yamapx700mk2blk | https://www.absolut… | NULL      | NULL              | 1                 | NULL           | NULL           | NULL               | NULL           | NULL               | NULL               | 2017-12-14    |
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------    ------------------------------------------------------------------------------

价格：

---------------------------------------------------------------------------------------------------------------------------
| price_pk | CREATION            | MODIFICATION | entity_id_id | customer_group_id | final_price | min_price | check_date |
---------------------------------------------------------------------------------------------------------------------------
| 260      | 2017-12-12 12:53:39 | NULL         | 15212        | 0                 | 109         | 109       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 261      | 2017-12-12 12:53:39 | NULL         | 15212        | 1                 | 109         | 109       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 262      | 2017-12-12 12:53:39 | NULL         | 15212        | 2                 | 109         | 109       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 263      | 2017-12-12 12:53:39 | NULL         | 15212        | 3                 | 109         | 109       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 264      | 2017-12-12 12:53:39 | NULL         | 15212        | 4                 | 109         | 109       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 265      | 2017-12-12 12:53:39 | NULL         | 15212        | 5                 | 109         | 109       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 266      | 2017-12-12 12:53:39 | NULL         | 15212        | 6                 | 109         | 109       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 988      | 2017-12-12 12:53:42 | NULL         | 15431        | 0                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 989      | 2017-12-12 12:53:42 | NULL         | 15431        | 1                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 990      | 2017-12-12 12:53:42 | NULL         | 15431        | 2                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 991      | 2017-12-12 12:53:42 | NULL         | 15431        | 3                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 992      | 2017-12-12 12:53:42 | NULL         | 15431        | 4                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 993      | 2017-12-12 12:53:42 | NULL         | 15431        | 5                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 994      | 2017-12-12 12:53:42 | NULL         | 15431        | 6                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 1002     | 2017-12-12 12:53:42 | NULL         | 15433        | 0                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 1003     | 2017-12-12 12:53:42 | NULL         | 15433        | 1                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 1004     | 2017-12-12 12:53:42 | NULL         | 15433        | 2                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 1005     | 2017-12-12 12:53:42 | NULL         | 15433        | 3                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 1006     | 2017-12-12 12:53:42 | NULL         | 15433        | 4                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 1007     | 2017-12-12 12:53:42 | NULL         | 15433        | 5                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------
| 1008     | 2017-12-12 12:53:42 | NULL         | 15433        | 6                 | 545         | 545       | NULL       |
---------------------------------------------------------------------------------------------------------------------------

这些在 Magento_Id (magento) 字段上连接在一起，该字段是一个整数。产品表中有我们正确的价格价格表包含网站上针对不同客户群的 magento 价格

每个产品可以有很多价格，我希望根据我们的内部数据库检查价格是否正确（因此网站是正确的）

我编写了一个 SQL 查询，显示价格表中的价格与 Product 表中的价格不相等的位置。

我也在 PeeWee Orm 中得到了这个工作。

然而，我正在努力让 peewee 向我展示 Price 表中的 final_price，即使我的 SQL 查询使用它作为比较器。

示例 SQL：

 SELECT
 sku, magento_id, fm_price, price.final_price, `url`
 FROM
 products
 JOIN
 price
 ON
 `products`.`magento_id` = `price`.`entity_id_id` AND `price`.`customer_group_id` = 0
 WHERE
 `products`.`fm_price` != `price`.`final_price`

示例输出：

---------------------------------------------------------------------------------------------------------------
| sku            | magento_id | fm_price | final_price | url                                                  |
---------------------------------------------------------------------------------------------------------------
| bsrhtstudio20h | 17581      | 399      | 449         | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx |
---------------------------------------------------------------------------------------------------------------
| rolac60rw      | 17697      | 479      | 475         | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx |
---------------------------------------------------------------------------------------------------------------
| yamthr5        | 17833      | 169.85   | 169         | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx |
---------------------------------------------------------------------------------------------------------------
| rolgk3b        | 19636      | 155      | 152         | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx |
---------------------------------------------------------------------------------------------------------------
| rolgk3         | 19763      | 155      | 152         | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx |
---------------------------------------------------------------------------------------------------------------
| bosac3         | 20115      | 113      | 107.15      | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx |
---------------------------------------------------------------------------------------------------------------
| bosbd2         | 20128      | 79       | 77.95       | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx |
---------------------------------------------------------------------------------------------------------------
| bosch1         | 20140      | 77.5     | 71.92       | xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx |
---------------------------------------------------------------------------------------------------------------

还有我的 Peewee 查询

price_errors = Product.select(Product, Price.final_price).join(Price, on=(Product.magento == Price.entity_id) & (
            Price.customer_group_id == 0)).where(Product.fm_price != Price.final_price)

这给了我正确的结果，但我无法访问要显示的 Price.final_price

我尝试了以下方法：

对于 price_errors 中的 price_error：打印（price_error.price.final_price）

给出：

AttributeError: 'Product' object has no attribute 'price'

我可以访问price_set，但这显示了所有通过外键连接相关的项目，而不是上面指定的连接

我已经在 join 和 select 中添加了别名，但仍然无法得到任何东西。

如果我用

执行它

price_errors = Product.raw("""SELECT id, sku, magento_id, fm_price, 
price.final_price, `url`
                                FROM products
                                JOIN price
                                ON `products`.`magento_id` = 
`price`.`entity_id_id` AND `price`.`customer_group_id` = 0
                                WHERE `products`.`fm_price` != 
`price`.`final_price`""")

然后我可以访问 price_error.final_price

但是这种方式破坏了 orm 的使用 :(

【问题讨论】：

标签： python sql orm peewee

【解决方案1】：

试试：

for product in price_errors:
     print product.price.final_price

【讨论】：

感谢您的回复，我的意思是记下我尝试过的所有排列，作为其中之一，我现在将更新问题
在您的 join on=expression 中，尝试添加别名：.join((exp1... exp2).alias('price'))
price_errors = Product.select(Product, Price.final_price.alias('fprice')).join(Price, on=(Product.magento == Price.entity_id) & ( Price.customer_group_id = = 0)).alias('test_price').where(Product.fm_price != Price.final_price) - 仍然无法通过 fprice、price、test_price 等访问:(