Find oldest/youngest post in mongodb collection

mongodb datetime aggregation-framework datetime-format
user3799658 picture user3799658 · Feb 10, 2015 · Viewed 13.1k times · Source

I have a mongodb collection with many fields. One field is 'date_time', which is in an ISO datetime format, Ex: ISODate("2014-06-11T19:16:46Z"), and another field is 'name'.

Given a name, how do I find out the oldest/youngest post in the collection?

Ex: If there are two posts in the collection 'data' : 

[{'name' : 'John', 'date_time' : ISODate("2014-06-11T19:16:46Z")},
 {'name' : 'John', 'date_time' : ISODate("2015-06-11T19:16:46Z")}]

Given the name 'John' how do I find out the oldest post in the collection i.e., the one with ISODate("2014-06-11T19:16:46Z")? Similarly for the youngest post.

Answer

wdberkeley picture wdberkeley · Feb 10, 2015

Oldest:

db.posts.find({ "name" : "John" }).sort({ "date_time" : 1 }).limit(1)

Newest:

db.posts.find({ "name" : "John" }).sort({ "date_time" : -1 }).limit(1)

Index on { "name" : 1, "date_time" : 1 } to make the queries efficient.

Related questions

Find objects between two dates MongoDB

I've been playing around storing tweets inside mongodb, each object looks like this: { "_id" : ObjectId("4c02c58de500fe1be1000005"), "contributors" : null, "text" : "Hello world", "user" : { "following" : null, "followers_count" : 5, "utc_offset" : null, "location" : "", "profile_text_color" : "000000", "friends_count" : 11, "profile_…

Read More
Best way to store date/time in mongodb

I've seen using strings, integer timestamps and mongo datetime objects.

Read More
Query Mongodb on month, day, year... of a datetime

I'm using mongodb and I store datetime in my database in this way for a date "17-11-2011 18:00" I store: date = datetime.datetime(2011, 11, 17, 18, 0) db.mydatabase.mycollection.insert({"date" : date}) I would like to do a request like that month = 11 db.…

Read More