Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
How to get distinct list of sub-document field values in MongoDB?
To get distinct list of sub-document field values, you can use dot(.). The syntax is as follows −
db.yourCollectionName.distinct("yourOuterFieldName.yourInnerFieldName");To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −
> db.getDistinctListOfSubDocumentFieldDemo.insertOne(
... {
... "StudentId": 101,
... "StudentPersonalDetails": [
... {
... "StudentName": "John",
... "StudentAge":24
... },
... {
... "StudentName": "Carol",
... "StudentAge":21
... }
... ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5c90a9abb74d7cfe6392d7d8")
}
> db.getDistinctListOfSubDocumentFieldDemo.insertOne(
...
... {
... "StudentId": 102,
... "StudentPersonalDetails": [
... {
... "StudentName": "Carol",
... "StudentAge":26
... },
... {
... "StudentName": "Bob",
... "StudentAge":21
... }
... ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5c90a9ceb74d7cfe6392d7d9")
}
> db.getDistinctListOfSubDocumentFieldDemo.insertOne(
... {
... "StudentId": 103,
... "StudentPersonalDetails": [
... {
... "StudentName": "Bob",
... "StudentAge":25
... },
... {
... "StudentName": "David",
... "StudentAge":24
... }
... ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5c90a9e6b74d7cfe6392d7da")
}Display all documents from a collection with the help of find() method. The query is as follows −
> db.getDistinctListOfSubDocumentFieldDemo.find().pretty();
The following is the output −
{
"_id" : ObjectId("5c90a9abb74d7cfe6392d7d8"),
"StudentId" : 101,
"StudentPersonalDetails" : [
{
"StudentName" : "John",
"StudentAge" : 24
},
{
"StudentName" : "Carol",
"StudentAge" : 21
}
]
}
{
"_id" : ObjectId("5c90a9ceb74d7cfe6392d7d9"),
"StudentId" : 102,
"StudentPersonalDetails" : [
{
"StudentName" : "Carol",
"StudentAge" : 26
},
{
"StudentName" : "Bob",
"StudentAge" : 21
}
]
}
{
"_id" : ObjectId("5c90a9e6b74d7cfe6392d7da"),
"StudentId" : 103,
"StudentPersonalDetails" : [
{
"StudentName" : "Bob",
"StudentAge" : 25
},
{
"StudentName" : "David",
"StudentAge" : 24
}
]
}Here is the query to get the distinct list of sub-document field values −
> db.getDistinctListOfSubDocumentFieldDemo.distinct("StudentPersonalDetails.StudentName");The following is the output −
[ "Carol", "John", "Bob", "David" ]
Updated on: 30-Jul-2019
218 Views
Advertisements