db.command.aggregate.multiply

1. 操作符描述

功能：取传入的数字参数相乘的结果。

声明：db.command.aggregate.multiply([expression1, expression2, ...])

2. 操作符参数

字段	类型	必填	说明
-	Expression	是	参数可以是任意解析为数字的表达式。

3. 示例代码

假设集合 fruits 有如下记录：

{ "_id": 1, "name": "apple", "price": 10, "quantity": 100 }{ "_id": 2, "name": "orange", "price": 15, "quantity": 50 }{ "_id": 3, "name": "lemon", "price": 5, "quantity": 20 }

求各个水果的的总价值：

// 云函数环境下示例代码const tcb = require('@cloudbase/node-sdk')const app = tcb.init({  env: 'xxx'})
const db = app.database()const $ = db.command.aggregateconst _ = db.command
exports.main = async (event, context) => {  const res = await db    .collection('fruits')    .aggregate()    .project({      name: 1,      total: $.multiply(['$price', '$quantity'])    })    .end()  console.log(res.data)}

返回结果如下：

{ "_id": 1, "name": "apple", "total": 1000 }{ "_id": 2, "name": "orange", "total": 750 }{ "_id": 3, "name": "lemo", "total": 100 }