MongoDB: How to query for records where field is null or not set?

mongodb null mongodb-query exists
Andrew picture Andrew · May 14, 2012 · Viewed 118.2k times · Source

I have an Email document which has a sent_at date field:

{
  'sent_at': Date( 1336776254000 )
}

If this Email has not been sent, the sent_at field is either null, or non-existant.

I need to get the count of all sent/unsent Emails. I'm stuck at trying to figure out the right way to query for this information. I think this is the right way to get the sent count:

db.emails.count({sent_at: {$ne: null}})

But how should I get the count of the ones that aren't sent?

Answer

jdi picture jdi · May 14, 2012

If the sent_at field is not there when its not set then:

db.emails.count({sent_at: {$exists: false}})

If its there and null, or not there at all:

db.emails.count({sent_at: null})

Refer here for querying and null

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