Mongodb 按日期排序

Mongodb sort by date

提问by Joey

I have a document with a field _idhas type ObjectId, and a field created_athas type Date.

我有一个文档，其中一个字段_id有 type ObjectId，一个字段created_at有 type Date。

_idis of course increasing, and the value of created_atis current_date should be increasing.

_id当然是在增加，并且created_atis current_date的值应该在增加。

So my question is :

所以我的问题是：

1. Is there any chance that 2 documents, A and B, A._id > B._id, but A.created_at < B.created_at.
2. How to keep created_atas precise as possible, so the order of created_atcorresponds to _id.

1. 有没有可能 2 个文件，A 和 B A._id > B._id，，但是A.created_at < B.created_at.
2. 如何保持created_at尽可能精确，所以 的顺序created_at对应于_id.

回答by Sukanta

you can use order_by on documents collection like

您可以在文档集合上使用 order_by，例如

in Rails

在 Rails 中

Product.order_by("created_at desc")

in Mongodbfor example

以 Mongodb为例

db.products.find().sort({"created_at": 1}) --- 1 for asc and -1 for desc