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Search by property name for any document with that property in MongoDB?

karthikeya Boyini
karthikeya Boyini
Updated on 30-Jul-2019 266 Views

You can use $ne operator for this. Let us first create a collection with documents −> db.searchByPropertyName.insertOne({"FirstName":"Larry", "Age":23}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7af7219729fde21ddb5") } > db.searchByPropertyName.insertOne({"FirstName":null, "Age":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7b97219729fde21ddb6") } > db.searchByPropertyName.insertOne({"FirstName":"John", "Age":22}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7c57219729fde21ddb7") } > db.searchByPropertyName.insertOne({"FirstName":null, "Age":25}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7d07219729fde21ddb8") } > db.searchByPropertyName.insertOne({"FirstName":"David", "Age":20}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbaf7df7219729fde21ddb9") }Following is the query to display all documents from the collection with the help of find() prettyprint −> db.searchByPropertyName.find().pretty();This will produce ...

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Unset an attribute from a single array element in MongoDB?

Samual Sam
Samual Sam
Updated on 30-Jul-2019 216 Views

Use $unset operator to unset an attribute. Let us first create a collection with documents −> db.unsetAnAttributeDemo.insertOne( ...    { ...       _id: 1, ...       "StudentDetails": [ ...          { ...             "StudentFirstName": "Ramit", ...             "StudentCountryName":"UK" ...          }, ...          { ...             "StudentFirstName": "Bob", ...             "StudentCountryName":"US" ...          }, ...          { ...       ...

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How to query MongoDB using the $ne operator?

karthikeya Boyini
karthikeya Boyini
Updated on 30-Jul-2019 178 Views

To query MongoDB using the $ne operator, following is the syntax −db.yourCollectionName.find({yourFieldName:{$ne:yourValue}}).pretty();Let us create a collection with documents −> db.notEqaulToDemo.insertOne({"StudentName":"Larry", "StudentMathMarks":68}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd3a6bde8cc557214c0ded") } > db.notEqaulToDemo.insertOne({"StudentName":"Chris", "StudentMathMarks":88}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd3a79de8cc557214c0dee") } > db.notEqaulToDemo.insertOne({"StudentName":"David", "StudentMathMarks":45}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd3a89de8cc557214c0def") } > db.notEqaulToDemo.insertOne({"StudentName":"Carol", "StudentMathMarks":69}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd3a97de8cc557214c0df0") }Display all documents from a collection with the help of find() method −> db.notEqaulToDemo.find().pretty();This will produce the following output −{    "_id" : ObjectId("5cbd3a6bde8cc557214c0ded"),    "StudentName" : "Larry",    "StudentMathMarks" : ...

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Count distinct value in MongoDB?

Samual Sam
Samual Sam
Updated on 30-Jul-2019 433 Views

Use the concept of length to count distinct value. Following is the syntax −db.yourCollectionName.distinct("yourFieldName").length;Let us create a collection with documents −> db.countDistinctDemo.insertOne({"StudentName":"John"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd6166de8cc557214c0dfa") } > db.countDistinctDemo.insertOne({"StudentName":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd616ade8cc557214c0dfb") } > db.countDistinctDemo.insertOne({"StudentName":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd616cde8cc557214c0dfc") } > db.countDistinctDemo.insertOne({"StudentName":"Carol"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd6170de8cc557214c0dfd") } > db.countDistinctDemo.insertOne({"StudentName":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd6175de8cc557214c0dfe") } > db.countDistinctDemo.insertOne({"StudentName":"Carol"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd6181de8cc557214c0dff") }Display all documents from a collection with the help ...

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Create array with MongoDB query?

karthikeya Boyini
karthikeya Boyini
Updated on 30-Jul-2019 3K+ Views

You can use the concept of toArray() to create array. Following is the syntax −db.yourCollectonName.find({}, {yourFieldName:1}).toArray();Let us create a collection with documents −> db.createArrayDemo.insertOne({"UserName":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd6461de8cc557214c0e00") } > db.createArrayDemo.insertOne({"UserName":"David"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd6467de8cc557214c0e01") } > db.createArrayDemo.insertOne({"UserName":"Robert"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd646cde8cc557214c0e02") } > db.createArrayDemo.insertOne({"UserName":"Sam"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cbd6470de8cc557214c0e03") }Display all documents from a collection with the help of find() method −> db.createArrayDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cbd6461de8cc557214c0e00"), "UserName" : "Chris" } { "_id" : ObjectId("5cbd6467de8cc557214c0e01"), ...

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