楷模：
class Winner(models.Model): lucky_draw = models.ForeignKey(LuckyDraw) participation = models.ForeignKey(Participation) prize = models.ForeignKey(Prize) mobile_number = models.CharField(max_length=15,null=True,default = None)class PrizeVerificationCodeSMSLog(models.Model): winner = models.ForeignKey(Winner) mobile_number = models.CharField(max_length=15,db_index=True) created_on = models.DateTimeField(auto_now_add=True)@H_301_7@
因为mobile_number并不总是在Winner模型中填充,我想要的是拥有手机号码或获得短信的赢家.所以必须加入PrizeVerificationCodeSMSLog才能达到我的目的.
只有赢家很简单：
winners = models.Winner.objects.filter(lucky_draw_id=id).order_by('-created_on')[:10]@H_301_7@
但我不知道可以添加什么过滤器来加入PrizeVerificationCodeSMSLog.
我终于明白了如何在django中检索我想要的数据.
如果要让模型A受到另一个具有A外键的模型B的限制,请不要尝试使用filter().因为A不知道B,但B知道A！只需检索A基B.
最佳答案
尝试
logs = PrizeVerificationCodeSMSLog.objects.filter(winner__lucky_draw_id=id).order_by('-created_on')winners = logs.select_related("winner")[:10]@H_301_7@
SELECT "prizeverificationcodesmslog"."id","prizeverificationcodesmslog"."winner_id","prizeverificationcodesmslog"."mobile_number","prizeverificationcodesmslog"."created_on","winner"."id","winner"."lucky_draw_id","winner"."participation_id","winner"."prize_id","winner"."mobile_number" FROM "prizeverificationcodesmslog" INNER JOIN "winner" ON ("prizeverificationcodesmslog"."winner_id" = "winner"."id") WHERE "winner"."lucky_draw_id" = 1 ORDER BY "prizeverificationcodesmslog"."created_on" DESC LIMIT 10;@H_301_7@
我不确定您的要求是什么,但您可能希望通过Max PrizeVerificationCodeSMSLog进行聚合
见https://docs.djangoproject.com/en/1.5/topics/db/aggregation/