Aggregate.sample

1. Interface Description

Function: Aggregation stage. Randomly selects a specified number of records from the documents.

Declaration: sample({ size: <positive integer> })

2. Input Parameters

Parameter	Type	Required	Description
size	number	Yes	size must be a positive integer, otherwise an error will occur.

3. Response

Parameter	Type	Required	Description
-	Aggregate	Yes	Aggregation object

4. Sample Code

Suppose the document users contains the following records:

{ "name": "a" }
{ "name": "b" }

Sample Randomly

If a lottery is being conducted now and a lucky user needs to be selected, the sample method would be called as follows:

const tcb = require("@cloudbase/node-sdk");
const app = tcb.init({
  env: "xxx",
});

const db = app.database();
const { gt, sum, concat } = db.command.aggregate;

exports.main = async (event, context) => {
  const res = await db
    .collection("users")
    .aggregate()
    .sample({
      size: 1,
    })
    .end();
  console.log(res.data);
};

The record of a randomly selected user is returned as follows:

{ "_id": "696529e4-7e82-4e7f-812e-5144714edff6", "name": "b" }