For all elements of a field in MongoDB, use find() and in that, use $elemMatch. The $elemMatch operator matches documents that contain an array field with at least one element that matches all the specified query criteria.
Let us create a collection with documents −
> db.demo624.insertOne({"ListOfName":["John","Chris","David","Bob"]}); { "acknowledged" : true, "insertedId" : ObjectId("5e9ab3ff6c954c74be91e6a5") } > db.demo624.insertOne({"ListOfName":["John","Chris"]}); { "acknowledged" : true, "insertedId" : ObjectId("5e9ab4026c954c74be91e6a6") } > db.demo624.insertOne({"ListOfName":["John","Chris","Carol"]}); { "acknowledged" : true, "insertedId" : ObjectId("5e9ab4076c954c74be91e6a7") } > db.demo624.insertOne({"ListOfName":["John","Chris","Bob"]}); { "acknowledged" : true, "insertedId" : ObjectId("5e9ab40e6c954c74be91e6a8") } > db.demo624.insertOne({"ListOfName":["John","Chris","Mike","Robert"]}); { "acknowledged" : true, "insertedId" : ObjectId("5e9ab4186c954c74be91e6a9") }
Display all documents from a collection with the help of find() method −
> db.demo624.find();
This will produce the following output −
{ "_id" : ObjectId("5e9ab3ff6c954c74be91e6a5"), "ListOfName" : [ "John", "Chris", "David", "Bob" ] } { "_id" : ObjectId("5e9ab4026c954c74be91e6a6"), "ListOfName" : [ "John", "Chris" ] } { "_id" : ObjectId("5e9ab4076c954c74be91e6a7"), "ListOfName" : [ "John", "Chris", "Carol" ] } { "_id" : ObjectId("5e9ab40e6c954c74be91e6a8"), "ListOfName" : [ "John", "Chris", "Bob" ] } { "_id" : ObjectId("5e9ab4186c954c74be91e6a9"), "ListOfName" : [ "John", "Chris", "Mike", "Robert" ] }
Following is the query to see if all elements of a field are contained in a superset −
> db.demo624.find({"ListOfName":{$not:{$elemMatch:{$nin:["John", "Chris", "David", "Bob"]}}}});
This will produce the following output −
{ "_id" : ObjectId("5e9ab3ff6c954c74be91e6a5"), "ListOfName" : [ "John", "Chris", "David", "Bob" ] } { "_id" : ObjectId("5e9ab4026c954c74be91e6a6"), "ListOfName" : [ "John", "Chris" ] } { "_id" : ObjectId("5e9ab40e6c954c74be91e6a8"), "ListOfName" : [ "John", "Chris", "Bob" ] }