Comparison

$eq

Matches documents where the value of a field equals the specified value. It is equivalent to using the form { field: <value> }.

col.insert({"item": {"amount": 10}})
col.find({"item.amount": 10}) # found
col.find({"item.amount": {"$eq": 10}}) # found
col.find({"item.amount": {"$eq": 0}}) # None

$ne

Selects the documents where the value of the specified field is not equal to the specified value. This includes documents that do not contain the specified field.

col.insert({"item": {"amount": 10}})
col.find({"item.amount": {"$ne": 0}}) # found
col.find({"item.amount": {"$ne": 10}}) # None

$gt, $>

Selects the documents where the value of the specified field is greater than (i.e. >) the specified value.

col.insert({"item": {"amount": 10}})
col.find({"item.amount": {"$gt": 9}})  # found
col.find({"item.amount": {"$gt": 10}})  # None

$gte, $>=

Selects the documents where the value of the specified field is greater than or equal to (i.e. >=) the specified value.

col.insert({"item": {"amount": 10}})
col.find({"item.amount": {"$gte": 10}})  # found
col.find({"item.amount": {"$gte": 11}})  # None

$lt, $<

Selects the documents where the value of the specified field is less than (i.e. <) the specified value.

col.insert({"item": {"amount": 10}})
col.find({"item.amount": {"$lt": 11}})  # found
col.find({"item.amount": {"$lt": 10}})  # None

$lte, $<=

Selects the documents where the value of the specified field is less than or equal to (i.e. <=) the specified value.

col.insert({"item": {"amount": 10}})
col.find({"item.amount": {"$lte": 10}})  # found
col.find({"item.amount": {"$lt": 9}})  # None

$in

Selects the documents where the value of a field equals any value in the specified array.

col.insert({"item": {"amount": 10}})
col.find({"item.amount": {"$in": [5, 10, 15]}})  # found
col.find({"item.amount": {"$in": [5, 15]}})  # None

$nin

Selects the documents where the value of a field is not in the specified array or the specified field does not exist.

col.insert({"item": {"amount": 10}})
col.find({"item.amount": {"$nin": [5, 15]}})  # found
col.find({"item.amount": {"$nin": [5, 10, 15]}})  # None