Django跟某几个字段去重MySQL

创建一个Book表

from django.db import models

class Book(models.Model):
    book_name = models.CharField(max_length=256, verbose_name='名称')
    category = models.CharField(max_length=256, verbose_name='类型')
    price = models.IntegerField(verbose_name="价格")
)

方案一，推荐方案，查询速度明显高于方案二。

queryset = self.queryset.extra(where=[
        'book.id in (SELECT id FROM book WHERE category=Python GROUP BY price, book_name)'
    ])

方案二，根据price和book_name字段去重查询category为Python的数据

queryset = Book.objects.filter(
    id__in=[i.id for i in Book.objects.raw(
        "SELECT * FROM book where category=%s GROUP BY price, book_name",
        ["Python"]
    )]
)

其实下面这一句查询条件就足够查到需要的数据，但是使用raw查出来的并不是一个QuerySet对象，想要继续在queryset的基础上继续查询，就需要再进行一次转换。

queryset = Book.objects.raw("SELECT * FROM book where category=%s GROUP BY price, book_name", ["Python"])