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Get Random record from MongoDB?
To get a random record from MongoDB, you can use aggregate function. The syntax is as follows:
db.yourCollectionName.aggregate([{$sample:{size:1}}]);To understand the above syntax, let us create a collection with some documents. The query to create collection is as follows:
>db.employeeInformation.insert({"EmployeeId":1,"EmployeeName":"Maxwell","EmployeeAge":26});
WriteResult({ "nInserted" : 1 })
>db.employeeInformation.insert({"EmployeeId":2,"EmployeeName":"David","EmployeeAge":25});
WriteResult({ "nInserted" : 1 })
>db.employeeInformation.insert({"EmployeeId":3,"EmployeeName":"Carol","EmployeeAge":24});
WriteResult({ "nInserted" : 1 })
>db.employeeInformation.insert({"EmployeeId":4,"EmployeeName":"Bob","EmployeeAge":28});
WriteResult({ "nInserted" : 1 })
>db.employeeInformation.insert({"EmployeeId":5,"EmployeeName":"Sam","EmployeeAge":27);
WriteResult({ "nInserted" : 1 })Now you can display all documents from a collection with the help of find() method. The query is as follows:
> db.employeeInformation.find().pretty();
The following is the output:
{
"_id" : ObjectId("5c6d3079734e98fc0a434ae5"),
"EmployeeId" : 1,
"EmployeeName" : "Maxwell",
"EmployeeAge" : 26
}
{
"_id" : ObjectId("5c6d308c734e98fc0a434ae6"),
"EmployeeId" : 2,
"EmployeeName" : "David",
"EmployeeAge" : 25
}
{
"_id" : ObjectId("5c6d309d734e98fc0a434ae7"),
"EmployeeId" : 3,
"EmployeeName" : "Carol",
"EmployeeAge" : 24
}
{
"_id" : ObjectId("5c6d30ab734e98fc0a434ae8"),
"EmployeeId" : 4,
"EmployeeName" : "Bob",
"EmployeeAge" : 28
}
{
"_id" : ObjectId("5c6d30bb734e98fc0a434ae9"),
"EmployeeId" : 5,
"EmployeeName" : "Sam",
"EmployeeAge" : 27
}Here is the query to get random record:
> db.employeeInformation.aggregate([{$sample:{size:1}}]).pretty();The following is the output:
{
"_id" : ObjectId("5c6d30bb734e98fc0a434ae9"),
"EmployeeId" : 5,
"EmployeeName" : "Sam",
"EmployeeAge" : 27
}Let us get another random record using the same query:
> db.employeeInformation.aggregate([{$sample:{size:1}}]).pretty();The following is the output:
{
"_id" : ObjectId("5c6d308c734e98fc0a434ae6"),
"EmployeeId" : 2,
"EmployeeName" : "David",
"EmployeeAge" : 25
}
Updated on: 30-Jul-2019
1K+ Views
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