Question

我正在学习Django，并且在StackOverflow上使用文档和其他各种文章已经走了很长一段路，但是现在我有点卡住了。本质上，我想按如下方式查询数据库：

SELECT 
    w.wname,
    w.act_owner_id,
    wi.act_code, 
    wi.act_provider, 
    SUM(ft.quantity) AS "position", 
    prices.Current,
    prices.MonthEnd,
    prices.YearEnd,
    cost.avgcost,
    sec.securityName AS "security" 
FROM 
    finance_wrapperinstance as wi
INNER JOIN finance_wrapper as w ON
    (w.id = wi.wrapperType_id)
INNER JOIN finance_security as sec ON
    (ft.security_id = sec.id)
left outer JOIN finance_transaction as ft ON 
    (wi.id = ft.investwrapperID_id) 
left outer Join 
    (SELECT
        hp.security_id as secid,
        max(Case when hp.date = '2019-11-18' then hp.price end) as 'Current',
        max(Case when hp.date = '2019-10-30' then hp.price end) as 'MonthEnd',
        max(Case when hp.date = '2018-12-31' then hp.price end) as 'yearEnd'
    FROM finance_historicprice as hp
    GROUP BY hp.security_id
    ) AS prices ON 
    (prices.secid =ft.security_id)
INNER JOIN 
    (SELECT
        trans.security_id AS secid,
        trans.investwrapperID_id as iwID,
        SUM((CASE WHEN trans.buysell = 'b' THEN trans.quantity ELSE 0 END)* trans.price) /
        SUM(CASE WHEN trans.buysell = 'b' THEN trans.quantity ELSE 0 END) AS avgCost
    FROM 
        finance_transaction as trans
    GROUP BY
        trans.security_id,
        trans.investwrapperID_id) AS cost ON
        (cost.secid = ft.security_id and cost.iwID = wi.id)

GROUP BY 
    w.wname,
    wi.wrapperType_id, 
    wi.act_code, 
    wi.act_provider, 
    ft.security_id

但是我不知道如何使用Django ORM来获取我的 prices 子查询或 cost 子查询。

模型如下所示：

class Wrapper(models.Model):
    wname = models.CharField(max_length=50,null=False,verbose_name="Wrapper Name")
    act_owner = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)

class Wrapperinstance(models.Model):
    wrapperType = models.ForeignKey(Wrapper,on_delete=models.CASCADE)
    act_code = models.CharField(max_length=50,null=False, verbose_name="Account Code")
    act_provider = models.CharField(max_length=50,null=False,verbose_name="Account Provider")

class Security(models.Model):
    securityName    = models.CharField(max_length=200,null=False,verbose_name="Security Name")
    securityType    = models.ForeignKey(InstrumentType,on_delete=models.CASCADE)

class Transaction(models.Model):
    BUY = 'b'
    SELL = 's'
    BUY_SELL_CHOICES = [
        (BUY, 'Buy'),
        (SELL, 'Sell'),
    ]

    security        = models.ForeignKey(Security,default=1,on_delete=models.CASCADE)
    investwrapperID = models.ForeignKey(Wrapperinstance,default=1,on_delete=models.CASCADE)
    quantity        = models.DecimalField(max_digits=14, decimal_places=4)
    buysell         = models.CharField(max_length=2,choices=BUY_SELL_CHOICES, default = BUY)
    price           = models.DecimalField(max_digits=14, decimal_places=2)


class HistoricPrice(models.Model):
    security        = models.ForeignKey(Security,default=1,on_delete=models.CASCADE)
    date            = models.DateField()
    price           = models.DecimalField(max_digits=14, decimal_places=2)

任何帮助或指针将不胜感激。另外，我有一些函数可以选择要为SQL查询输入的正确日期。这再次使我认为RAW方法可能是可行的方法。

Django-我可以在没有原始查询的情况下执行此操作

0 个答案: