I have an array of ids and I want to get all document of them at once. For that I am writing but it return 0 records.
How can I search using multiple Ids ?
I believe you are missing the ObjectId. Try this:
ObjectId
db.feed.find({ _id: { $in: [ObjectId("55880c251df42d0466919268"), ObjectId("55bf528e69b70ae79be35006")] } });