sqlalchemy + flask ，按天获取所有帖子 [英] sqlalchemy + flask , getting all post by day

问题描述

我有一张桌子，posts.

其中包括:

id = db.Column(db.Integer, primary_key=True)
title = db.Column(db.String(200))
content =  db.Column(db.Text())
time = db.Column(db.DateTime)

当我导航到这个 url 时，这就是我想要实现的目标.

this is what I am trying to achieve when I navigate to this url.

/allposts

posts on 01-01-2013
 - post 1
 - post 2
 - post 3 

posts on 01-02-2013
 - post 4
 - post 5
 - post 6

等等.

我尝试过 group by 但我无法实现我上面解释的内容.

I have tried group by but I couldn't achieve what I explained above.

我正在使用 sqlalchemy 和 Flask python 框架.

I am using sqlalchemy and flask python framework.

同时提供原始查询和 sqlalhemy 查询会好得多，因此我可以在这里概括一些概念.

providing both , raw and sqlalhemy queries will be much better so I can wrap my head around some of the concepts here.

谢谢！

推荐答案

我不会在查询中这样做，而是在 python 端创建所需的分组:

I would not do it in a query, but rather create desired grouping on the python side:

# get desired posts (add your filters etc)
posts = session.query(Post).order_by(Post.time)

# create a dictionary, where key is the date(-only), and values are the posts of that day
from collections import defaultdict
grouped = defaultdict(list)
for post in posts:
    dat = post.time.date()
    grouped[dat].append(post)

# iterate over new grouped structure
for dat, posts in sorted(grouped.items()):
    print dat
    for post in posts:
        print '  ', post

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