Question

为了开始使用Django，我正在使用它为我的垒球队建立一个小站点，我们可以列出每个球员的统计数据。对于模型，我已经定义了2个表 - Player和Statline，其中Statline中的玩家是外键。

class Player(models.Model):
    name = models.CharField(max_length=32)
    gender = models.CharField(max_length=1, choices=GENDER_CHOICES)
    bats = models.CharField(max_length=1, choices=HANDED_CHOICES)
    throws = models.CharField(max_length=1, choices=HANDED_CHOICES)
    position = models.CharField(max_length=2, choices=POSITION_CHOICES)
    pitches = models.CharField(max_length=1, choices=PITCHES_CHOICES)
    hometown = models.CharField(max_length=32)

    def __unicode__(self):
        return self.name

class StatLine(models.Model):
    season_name = models.CharField(max_length=12, choices=SEASON_CHOICES)
    player = models.ForeignKey(Player)
    at_bats = models.IntegerField(max_length=2, choices=NUMBER_CHOICES, default=0)
    singles = models.IntegerField(max_length=2, choices=NUMBER_CHOICES, default=0)
    doubles = models.IntegerField(max_length=2, choices=NUMBER_CHOICES, default=0)
    triples = models.IntegerField(max_length=2, choices=NUMBER_CHOICES, default=0)
    homeruns = models.IntegerField(max_length=2, choices=NUMBER_CHOICES, default=0)
    runs = models.IntegerField(max_length=2, choices=NUMBER_CHOICES, default=0)
    rbis = models.IntegerField(max_length=2, choices=NUMBER_CHOICES, default=0)
    rboe = models.IntegerField(max_length=2, choices=NUMBER_CHOICES, default=0)

我要做的是做一个查询，我总结每个玩家的所有统计数据并按玩家分组。这样我每个赛季的所有统计数据都有一个运行记录。在SQL中，当我用PHP构建网站时，它是：

FROM Stats
INNER JOIN Players ON Players.player_id = Stats.player_id 
WHERE season_name = 'Spring 2012'
GROUP BY Players.player_name

我对如何使用Django执行相同的查询感到困惑。任何帮助将不胜感激！

Answer 1

Django's documentation about aggregation就足够了。

我不知道你为什么要按player_name进行分组，因为你没有说明你想要选择哪些字段以及某处应该有聚合。是否可以为单个StatLine提供多个Player个对象？

如果你想要为每个玩家总结一个特定季节的所有本垒打，你可以使用这个片段：

from django.db.models import Sum
Player.objects.filter(
      statline__season_name="Spring 2012"
   ).annotate(
      sum_homeruns=Sum(statline__homeruns),
      sum_abats=Sum(statline__abats),
      sum_singles=Sum(statline__singl‌es),
      […]
)

作为stated in the docs，filter()和annotate()的顺序非常重要。

如何打印出一个访问Django中2个表的HTML表？

1 个答案: