MongoDB: How to execute a query to result of another query (nested queries)?

Question

I need to apply a set of filters (queries) to a collection. By default, the MongoDB applies AND operator to all queries submitted to find function. Instead of whole AND I need to apply each query sequentially (one by one). That is, I need to run the first-query and get a set of documents, run the second-query to result of first-query, and so on.

Is this Possible?

db.list.find({..q1..}).find({..q2..}).find({..q3..});

Instead Of:

db.list.find({..q1..}, {..q2..}, {..q3..});

Why do I need this?

Bcoz, the second-query needs to apply an aggregate function to result of first-query, instead of applying the aggregate to whole collection.

First and second queries do the same operation. Seems it obvious.. — Andrew Orsich
– Andrew Orsich, Commented Dec 22, 2010 at 6:09
But first query is currently not possible in MongoDB. Thats what my question is how to achieve the first query. — Prabu Arumugam
– Prabu Arumugam, Commented Dec 24, 2010 at 6:19

Rupeshit · Accepted Answer · 2010-12-21 10:27:53Z

2

Yes this is possible in MongoDB. You can write nested queries as per the requirement.Even in my application I created nested MongoDb queries.If you are familiar with SQL syntax then compare this with in of sql syntax:

     select cname from table where cid in (select .....)

In the same way you can create nested MongoDB queries on different collections also.

answered Dec 21, 2010 at 10:27

Rupeshit

1,4661 gold badge14 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Prabu Arumugam Over a year ago

Thanks for the suggestion. This solves the problem but have to be careful about performance of $in operator in nested queries.

Rupeshit Over a year ago

Yes, definitely you need to be concern that factor also before writing nested queries.And if it solves your problem then accept it so others having same problem will get solution.

Collectives™ on Stack Overflow

MongoDB: How to execute a query to result of another query (nested queries)?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related