How to make nested queries in MongoDb that works like nested Sql select queries

Question

I want to make an efficient query in MongoDb to find all users who have their userids listed in a usergroup. Ideally I want to make this as a single request to Mongodb. What I w

Answer 1

I was wondering the same thing about nested queries in mongodb. For my case, I putz a bit and got it to work and I think yours would too by using the "$or" and use toArray()

db.user.find({$or:db.usergroup.find({_id:"g1"},{_id:0,Users:1}).toArray()})

May not have that quite right but this is an example with my data that worked using a nexted query. Obviously a little silly as why feed ids back into another query in this case but wanted to see if it would work and it did:

db.notification.find({$or:db.notification.find({'startDate': { '$gte': ISODate("2019-08-01") }},{_id:1}).limit(10).toArray()})