如何将下面的 SQL 状态转换为 Django ORM

Question

很难将下面的 SQL 语句转换为 Django ORM。非常感谢任何帮助。

SELECT a.state, 
       a.city, 
       a.postcode, 
       b.rate_authority, 
       b.rate, 
       b.rate_descr 
FROM   fileload_taxratemodel AS a 
       INNER JOIN fileload_taxrateresponsemodel AS b 
               ON b.jurs_id_id = a.id 
ORDER  BY state ASC

Django 模型：

正在尝试根据外键从两个模型中提取字段。

class TaxRateModel(models.Model):

company_code = models.CharField(max_length = 10)
document_date = models.DateTimeField()
country = models.CharField(max_length = 30, default = "US")
province = models.CharField(max_length = 100, null= True,blank= True)
state = models.CharField(max_length = 100)
county = models.CharField(max_length = 100,blank=True, null=True)
city = models.CharField(max_length = 100,blank=True, null=True)
district = models.CharField(max_length = 100, blank=True, null=True)
postcode = models.CharField(max_length = 5, blank=True, null=True)
rate_code = models.CharField(max_length = 30,default = "ST")

Django 第二模型：

class TaxRateResponseModel(models.Model):
jurs_id = models.ForeignKey(TaxRateModel,on_delete=models.CASCADE,related_name='rates')
rate_authority = models.CharField(max_length = 100, blank=True, null=True, default='')
rate_descr = models.CharField(max_length = 100, blank=True, null=True, default ='')
rate = models.DecimalField(max_digits= 10, decimal_places=5)

Answer 1

假设您在名为 horaire:

的 django 应用程序中拥有这些模型

class A(models.Model):
    city = models.CharField(max_length=200, null=True, blank=True)
    postcode = models.CharField(max_length=200, null=True, blank=True)
    state = models.CharField(max_length=200, null=True, blank=True)


class B(models.Model):
    jurs_id = models.ForeignKey(A, related_name="ab", on_delete=models.DO_NOTHING)
    rate_authority = models.CharField(max_length=200, null=True)
    rate = models.CharField(max_length=200, null=True)
    rate_descr = models.CharField(max_length=200, null=True)

在你的 django 中 shell 你可以这样做：

$> from horaire.models import B
$> items = B.objects.values(
       'jurs_id__city',
       'jurs_id__state',
       'jurs_id__postcode',
       'rate_authority',
       'rate',
       'rate_descr'
   ).order_by('jurs_id__state')
$> print(items.query)
SELECT 
    "horaire_a"."city", 
    "horaire_a"."state", 
    "horaire_a"."postcode",
    "horaire_b"."rate_authority",
    "horaire_b"."rate",
    "horaire_b"."rate_descr" 
FROM "horaire_b" 
    INNER JOIN "horaire_a" ON ("horaire_b"."jurs_id_id" = "horaire_a"."id") 
ORDER BY "horaire_a"."state" ASC

或者，您可以这样做：

$> from horaire.models import A
$> items = A.objects.values(
       'city',
       'postcode',
       'state',
       'ab__rate_authority',
       'ab__rate',
       'ab__rate_descr'
   ).order_by('state')
$> print(items.query)
SELECT 
    "horaire_a"."city", 
    "horaire_a"."postcode", 
    "horaire_a"."state", 
    "horaire_b"."rate_authority", 
    "horaire_b"."rate", 
    "horaire_b"."rate_descr" 
FROM "horaire_a" 
    LEFT OUTER JOIN "horaire_b" ON ("horaire_a"."id" = "horaire_b"."jurs_id_id") 
ORDER BY "horaire_a"."state" ASC

然而，如您所见，在最终的 SQL 查询中没有任何 ALIAS，而且我没有找到使用 DJANGO ORM 实现它的相关方法（请参阅这个answer for more details）。除此之外，您始终可以传递 Raw SQL，当然您也可以编写自定义 SQL 查询，稍后您可以在您的应用程序下使用数据。有关 Raw SQL in Django 的更多信息，请访问此 documentation link

如何将下面的 SQL 状态转换为 Django ORM

How to convert SQL states below to Django ORM

python

sql

django

django-orm