How to choose a random document

Question

PHP

Good evening.
How to select a random document from a MongoDB collection?

Answer 1

Here is a similar question with multiple answers: Random record from MongoDB .
To recap the option that got the most votes there: find the number of entries in the collection and skip yourRandomNumber = (int)(rand() * count) entries:

db.yourCollection.find().limit(-1).skip(yourRandomNumber).next()

Answer 2

In The MongoDB Cookbook, this is The Random Attribute .

Answer 3

Do documents have integer sequential id's? Here, in Mysql in PHP, this is easily solved: we get max_id and min_id, generate 20 random numbers in this range and select SELECT * FROM table WHERE id IN (20 random numbers) LIMIT 1. It works great, through indexes, without any perversions.