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
Getting unique values within two arrays in one MongoDB document
To get unique values within two arrays in a document, use a $setUnion in aggregate(). The $setUnion takes two or more arrays and returns an array containing the elements that appear in any input array.
Let us create a collection with documents −
>db.demo608.insertOne({"ListOfName1":["John","Chris","Bob","David"],"ListOfName2":["Bob", "Sam","John","Robert","Chris"]}
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e974542f57d0dc0b182d62b")
}Display all documents from a collection with the help of find() method −
> db.demo608.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5e974542f57d0dc0b182d62b"),
"ListOfName1" : [
"John",
"Chris",
"Bob",
"David"
],
"ListOfName2" : [
"Bob",
"Sam",
"John",
"Robert",
"Chris"
]
}Following is the query to get unique values within two arrays in one MongoDB document −
> db.demo608.aggregate([
... {$project:{SetOfNames:{$setUnion:['$ListOfName1','$ListOfName2']}}}
... ]).pretty();This will produce the following output −
{
"_id" : ObjectId("5e974542f57d0dc0b182d62b"),
"SetOfNames" : [
"Bob",
"Chris",
"David",
"John",
"Robert",
"Sam"
]
}
Updated on: 15-May-2020
1K+ Views
Advertisements