MongoDB: Find a document by non-existence of a field?
Is there a way to specify a condition of "where document doesn't contain field" ?
For example, I want to only find the first of these 2 because it doesn't have the "price" field.
{"fruit":"apple", "color":"red"}
{"fruit":"banana", "color":"yellow", "price":"2.00"}
Possible duplicate of Mongo: find items that don't have a certain field
You can also try
db.mycollection.find({ "price" : null })
f
fracz
Try the $exists operator:
db.mycollection.find({ "price" : { "$exists" : false } })
and see its documentation.
+1. However, keep in mind that such queries can't use indexing and might be very slow on large collections.
Great point -- thanks. I know this caveat holds true in MongoDB version 1.8.x and before; but I thought queries with $exists field constraints can now make use of indexes in version 2.0 ...?
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