Basic Operations
An empty query document (i.e. {}) matches everything in the collection.
db.collections.find()
db.collections.find_one()
Add key/value pairs to restrict the search.
db.collections.find({<field> : <value>})
Add more key/value pairs for multiple conditions.
db.collections.find({<field1> : <value1>, <field2> : <value2>})
Pass a second argument to specify which keys to return/exclude.
db.collections.find({}, {<field1> : 1, <field2> : 1})
db.collections.find({}, {<field1> : 1, <field2> : 0}) # never want to return<field2>
Operators
$lt and $lte
db.collection.find({'field' : {'$lt': 2}})
db.collection.find({'field' : {'$lte': 1}})
$gt and $gte
db.collection.find({'field' : {'$gt': 1}})
db.collection.find({'field' : {'$gte': 2}})
$ne
db.collection.find({'field' : {'$ne' : 'value'}})
$in and $nin
db.collection.find({'field' : {'$in' : ['element_1', 'element_2']}})
db.collection.find({'field' : {'$nin' : ['element_1', 'element_2']}})
$or
db.collection.find({"$or":[{'field_1' :'value'}, {'field_2' : 'value'}]})
$all
db.collection.find({ <field>: { $all: [ <value1>, <value2>, ... ] } })
$elemMatch
db.collection.find({"<array_field>":{"$elemMatch":{"<field>": "<value>"}}})
Query an Embedded Document or Array of Embedded Document
db.collection.find({"<array_field>.<field>": "<value>"})
$slice
db.collection.find({}, {"field":{"$slice": <limit>}})
db.collection.find({}, {"field":{"$slice":[<skip>, <limit>]}})
Cursor (?) operator
In PyMongo, sort() method must pass parameter as tuple
The Syntax of Sort, Skip, Limit are almost same with Mongo Shell
db.store.find().sort( [ ( '_id', -1 ), (‘name’,1) ] )
db.store.find().skip(3)
db.store.find().limit(2).skip(3)
MongoDB always performs in the order of sort first, skip second, and limit
Specifies the order in which the query returns matching document.
Note that below two queries return the same answer.
db.store.find().sort([('_id', -1)]).limit(2)
db.store.find().limit(2).sort([('_id', -1)])
Count documents in the store collection.
collection.count_documents({})
# OR
collection.find().count() # Deprecated
