MongoDB: Can't canonicalize query: BadValue unknown operator -

the data given follows:

{     "_id" : { "$oid" : "546b79a2e4b0f7bfbaa97cc7" },      "title" : "eyewitness: highlands, scotland",      "description" : "photographs guardian eyewitness series",      "timestamp" : "14/11/2014",      "category" : "news",      "url" : "http://www.theguardian.com/world/picture/2014/nov/14/1",      "source" : "http://www.theguardian.com/",     "mainstory" : "\n",     "keywords" : [ "wildlife", "scotland" ]  } 

but when use following command find something, error comes out

db.guardian.find({ "_id": {"$oid": '546b79a2e4b0f7bfbaa97cc7'}}) 

how can find document specific $oid.

you need convert id string objectid this:

db.guardian.find({ "_id": objectid("546b79a2e4b0f7bfbaa97cc7") }) 

the reason being { "$oid" : "546b79a2e4b0f7bfbaa97cc7"} same objectid("546b79a2e4b0f7bfbaa97cc7") in different format.

refer docs more details.