Querying null value in MongoDB

Question

Using pymongo I am trying to retrieve the documents in a collection that have a SmallUrl different from null. I\'m trying to get t

Answer 1

your query does not work because you should use 'Images.SmallUrl' instead of 'SmallUrl' for the key of query. my test collection:

> db.t.find()
{ "_id" : ObjectId("512cdbb365fa12a0db9d8c35"), "Images" : { "LargeUrl" : "http://aaa.com", "SmallUrl" : "http://bb.com" }, "Name" : "yy" }
{ "_id" : ObjectId("512cdc1765fa12a0db9d8c36"), "Images" : { "LargeUrl" : "http://aaa.com", "SmallUrl" : null }, "Name" : "yy" }

and my test query:

> db.t.find({'Images.SmallUrl': {$ne: null}})
{ "_id" : ObjectId("512cdbb365fa12a0db9d8c35"), "Images" : { "LargeUrl" : "http://aaa.com", "SmallUrl" : "http://bb.com" }, "Name" : "yy" }

Hope to help ^_^