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
Push query results into variable with MongoDB?
For this, you can use aggregate(). Let us create a collection with documents −
> db.demo142.insertOne({"Value":50});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e32e9c6fdf09dd6d08539b2")
}
> db.demo142.insertOne({"Value":45});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e32e9cafdf09dd6d08539b3")
}
> db.demo142.insertOne({"Value":60});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e32e9cdfdf09dd6d08539b4")
}
> db.demo142.insertOne({"Value":55});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e32e9d0fdf09dd6d08539b5")
}
> db.demo142.insertOne({"Value":50});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e32e9d9fdf09dd6d08539b6")
}Display all documents from a collection with the help of find() method −
> db.demo142.find();
This will produce the following output −
{ "_id" : ObjectId("5e32e9c6fdf09dd6d08539b2"), "Value" : 50 }
{ "_id" : ObjectId("5e32e9cafdf09dd6d08539b3"), "Value" : 45 }
{ "_id" : ObjectId("5e32e9cdfdf09dd6d08539b4"), "Value" : 60 }
{ "_id" : ObjectId("5e32e9d0fdf09dd6d08539b5"), "Value" : 55 }
{ "_id" : ObjectId("5e32e9d9fdf09dd6d08539b6"), "Value" : 50 }Following is the query to push query results into variable −
> var query = db.demo142.aggregate(
... { "$group": { "_id": null, "MaxValue": { "$max": "$Value" } } }
... ]);
> var largestValue= query.toArray()[0]["MaxValue"];
> printjson(largestValue);This will produce the following output −
60
Updated on: 31-Mar-2020
685 Views
Advertisements