Question

如果我有要过滤的ID列表，我该如何生成查询？例如：

[14, 44]会产生query.filter(tags__tag_id=14).filter(tags__tag_id=44)

>>> print(Place.objects.filter(tags__tag_id=14).filter(tags__tag_id=44).query)

SELECT "places_place"."id", "places_place"."address"
FROM "places_place"
INNER JOIN "places_placetag"
ON ("places_place"."id" = "places_placetag"."place_id")
INNER JOIN "places_placetag"
T4 ON ("places_place"."id" = T4."place_id")
WHERE ("places_placetag"."tag_id" = 14 AND T4."tag_id" = 44)

（我不知道上面SQL中的T4是什么，但无论如何，这是另一个问题）

我有一个hacky解决方案，但它太天真和看起来很糟糕，必须有一个更好的方法来做到这一点：

tag_ids = [14, 44]

query_string = 'Place.objects'
for tag_id in tag_ids:
    query_string += ('.filter(tags___tag_id=' + str(tag_id))

query = eval(query_string)

class Place(models.Model):
    address = models.CharField(max_length=123)

class PlaceTag(models.Model):
    place = models.ForeignKey('Place', models.CASCADE, 'tags')
    tag = models.ForeignKey('Tag', models.CASCADE, 'places')

class Tag(models.Model):
    tag = models.CharField(max_length=254)

Answer 1

这样做你想要的吗？

tag_ids = [11, 22, 33]  # Place must have all of these tags
query = Place.objects.all()
for tag_id in tag_ids:
    query = query.filter(tags___tag_id=tag_id)

如何在Django中生成查询？

1 个答案: