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
Fetch records from a subdocument array wherein id begins from 234 in MongoDB
To fetch records from a subdocument array, use $unwind along with $push. For ids beginning from 234, use regex in MongoDB.
Let us create a collection with documents −
> db.demo556.insertOne(
... {
... _id:101,
... details:[
... {
... id:"234336",
... Name:"Chris"
... },
... {
... id:"123456",
... Name:"Bob"
... },
... {
... id:"234987",
... Name:"Carol"
... },
... {
... id:"989768",
... Name:"David"
... },
... {
... id:"234888",
... Name:"Sam"
... },
... {
... id:"847656",
... Name:"John"
... }
... ]
... }
... );
{ "acknowledged" : true, "insertedId" : 101 }Display all documents from a collection with the help of find() method −
> db.demo556.find();
This will produce the following output −
{ "_id" : 101, "details" : [
{ "id" : "234336", "Name" : "Chris" },
{ "id" : "123456", "Name" : "Bob" },
{ "id" : "234987", "Name" : "Carol" },
{ "id" : "989768", "Name" : "David" },
{ "id" : "234888", "Name" : "Sam" },
{ "id" : "847656", "Name" : "John" }
] }Following is the query to fetch records from a subdocument array −
> db.demo556.aggregate({
... $match: {
... "_id": 101
... }
... }, {
... $unwind: "$details"
... }, {
... $match: {
... "details.id": {
... $regex: /^234/
... }
... }
... }, {
... $group: {
... _id: "$_id",
... "Detail": {
... $push: "$details"
... }
... }
... }).pretty();This will produce the following output −
{
"_id" : 101,
"Detail" : [
{
"id" : "234336",
"Name" : "Chris"
},
{
"id" : "234987",
"Name" : "Carol"
},
{
"id" : "234888",
"Name" : "Sam"
}
]
}
Updated on: 14-May-2020
54 Views
Advertisements