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Project specific array field in a MongoDB collection?
Let us first create a collection with documents −
> db.projectionAnElementDemo.insertOne(
... {
... "CustomerId":100,
... "CustomerDetails": [
... {
... "CustomerName": "Chris",
... "CustomerCountryName": "US"
... },
... {
... "CustomerName": "Robert",
... "CustomerCountryName": "UK"
... }
... ]
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd31c56b64f4b851c3a13ea")
}Following is the query to display all documents from a collection with the help of find() method −
> db.projectionAnElementDemo.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5cd31c56b64f4b851c3a13ea"),
"CustomerId" : 100,
"CustomerDetails" : [
{
"CustomerName" : "Chris",
"CustomerCountryName" : "US"
},
{
"CustomerName" : "Robert",
"CustomerCountryName" : "UK"
}
]
}Following is the query to project element in array field −
> db.projectionAnElementDemo.find({},{CustomerId:1, "CustomerDetails.CustomerName":1}).pretty();This will produce the following output −
{
"_id" : ObjectId("5cd31c56b64f4b851c3a13ea"),
"CustomerId" : 100,
"CustomerDetails" : [
{
"CustomerName" : "Chris"
},
{
"CustomerName" : "Robert"
}
]
}
Updated on: 30-Jul-2019
177 Views
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