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Select MongoDB documents where a field either does not exist, is null, or is false?
You can use $in operator for this. Let us first create a collection with a document. The query to create a collection with a document is as follows −
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":1,"StudentName":"Larry"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010215705caea966c557f")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":2,"StudentName":"Mike","hasAgeGreaterThanOrEqualTo18":true});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c90106a5705caea966c5580")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":3,"StudentName":"Carol","hasAgeGreaterThanOrEqualTo18":false});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010795705caea966c5581")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":4,"StudentName":"Sam","hasAgeGreaterThanOrEqualTo18":null});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010865705caea966c5582")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":5,"StudentName":"David","hasAgeGreaterThanOrEqualTo18":false});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010945705caea966c5583")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":6,"StudentName":"Chris","hasAgeGreaterThanOrEqualTo18":null});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010a45705caea966c5584")
}
> db.selectMongoDBDocumentsWithSomeCondition.insertOne({"StudentId":7,"StudentName":"Robert","hasAgeGreaterThanOrEqualTo18":true});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c9010b05705caea966c5585")
}Display all documents from a collection with the help of find() method. The query is as follows −
> db.selectMongoDBDocumentsWithSomeCondition.find().pretty();
The following is the output &minus
{
"_id" : ObjectId("5c9010215705caea966c557f"),
"StudentId" : 1,
"StudentName" : "Larry"
}
{
"_id" : ObjectId("5c90106a5705caea966c5580"),
"StudentId" : 2,
"StudentName" : "Mike",
"hasAgeGreaterThanOrEqualTo18" : true
}
{
"_id" : ObjectId("5c9010795705caea966c5581"),
"StudentId" : 3,
"StudentName" : "Carol",
"hasAgeGreaterThanOrEqualTo18" : false
}
{
"_id" : ObjectId("5c9010865705caea966c5582"),
"StudentId" : 4,
"StudentName" : "Sam",
"hasAgeGreaterThanOrEqualTo18" : null
}
{
"_id" : ObjectId("5c9010945705caea966c5583"),
"StudentId" : 5,
"StudentName" : "David",
"hasAgeGreaterThanOrEqualTo18" : false
}
{
"_id" : ObjectId("5c9010a45705caea966c5584"),
"StudentId" : 6,
"StudentName" : "Chris",
"hasAgeGreaterThanOrEqualTo18" : null
}
{
"_id" : ObjectId("5c9010b05705caea966c5585"),
"StudentId" : 7,
"StudentName" : "Robert",
"hasAgeGreaterThanOrEqualTo18" : true
}Here is the query to select MongoDB documents where a field either does not exist, is null, or is false −
> db.selectMongoDBDocumentsWithSomeCondition.find({ "hasAgeGreaterThanOrEqualTo18": {$in: [false,null]}}).pretty();The following is the output −
{
"_id" : ObjectId("5c9010215705caea966c557f"),
"StudentId" : 1,
"StudentName" : "Larry"
}
{
"_id" : ObjectId("5c9010795705caea966c5581"),
"StudentId" : 3,
"StudentName" : "Carol",
"hasAgeGreaterThanOrEqualTo18" : false
}
{
"_id" : ObjectId("5c9010865705caea966c5582"),
"StudentId" : 4,
"StudentName" : "Sam",
"hasAgeGreaterThanOrEqualTo18" : null
}
{
"_id" : ObjectId("5c9010945705caea966c5583"),
"StudentId" : 5,
"StudentName" : "David",
"hasAgeGreaterThanOrEqualTo18" : false
}
{
"_id" : ObjectId("5c9010a45705caea966c5584"),
"StudentId" : 6,
"StudentName" : "Chris",
"hasAgeGreaterThanOrEqualTo18" : null
}
Updated on: 30-Jul-2019
320 Views
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