Mongo: find items that don't have a certain field

mongodb null exists
bcmcfc picture bcmcfc · Apr 19, 2011 · Viewed 32.3k times · Source

How to search for documents in a collection that are missing a certain field in MongoDB?

Answer

Andrew Orsich picture Andrew Orsich · Apr 19, 2011

Yeah, it's possible using $exists:

db.things.find( { a : { $exists : false } } ); // return if a is missing

When is true, $exists matches the documents that contain the field, including documents where the field value is null. If is false, the query returns only the documents that do not contain the field.

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