获取queryset中最新的“组”对象

Question

我想获得一个包含最新“组”项目的查询集（按日期）。基本上有一种更漂亮（更有效）的方式：

# get the latest set of news. It may or may not be today. 
# TODO: this seems ugly, find a better way
latest = Article.objects.latest('published')
latest_items = Article.objects.filter(published__year=latest.published.year,
                                                 published__month=latest.published.month,
                                                 published__day=latest.published.day)

Answer 1

您的代码存在的问题是，它会执行两次操作并查询数据库的两倍。

您可以使用select_related查询一次（仅查询published数据）和order_by：

articles = Article.objects.select_related('published').order_by('published')

然后使用此查询集完成所有工作：

def getLatest(queryset):
    latest = queryset.first()
    if latest == None:
        return

    for obj in queryset:
        if obj.published__year == latest.published__year and obj.published__month == latest.published__month and obj.published__day == latest.published__day:
            yield obj
        else:
            return