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db.command.aggregate.in

1. 操作符描述#

功能:给定一个值和一个数组,如果值在数组中则返回 true,否则返回 false

声明:db.command.aggregate.in([value, array])

2. 操作符参数#

字段类型必填说明
-<Array>Expression聚合表达式数组,value 可以是任意表达式,

array 可以是任意解析为数组的表达式。 |

3. 示例代码#

假设集合 shops 有如下记录:

{ "_id": 1, "topsellers": ["bread", "ice cream", "butter"] }{ "_id": 2, "topsellers": ["ice cream", "cheese", "yagurt"] }{ "_id": 3, "topsellers": ["croissant", "cucumber", "coconut"] }

标记销量最高的商品包含 ice cream 的记录。

// 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('price')    .aggregate()    .project({      included: $.in('ice cream', '$topsellers')    })    .end()  console.log(res.data)}

返回结果如下:

{ "_id": 1, "included": true }{ "_id": 2, "included": true }{ "_id": 3, "included": false }