代码： // 云函数入口文件 const cloud = require('wx-server-sdk') cloud.init() const db = cloud.database() // 云函数入口函数 exports.main = async(event, context) => { const _ = db.command console.log(event) var CanSave = await db.collection('meetingRoomOrder').where( _.or([{ mDate: event.mDate, roomName: event.roomName, mSAllTime: _.and(_.gte(event.stime), _.lte(event.etime)), }, { mDate: event.mDate, roomName: event.roomName, mEAllTime: _.lte(event.etime), mSAllTime: _.gte(event.stime), }, { mDate: event.mDate, roomName: event.roomName, mEAllTime: _.gte(event.etime), mSAllTime: _.lte(event.stime), }, { mDate: event.mDate, roomName: event.roomName, mEAllTime: _.and(_.gte(event.stime), _.lte(event.etime)), } ]) ).get() console.log(CanSave) return { CanSave: CanSave } } 错误信息： 返回结果： Error: errCode: -502001 database request fail | errMsg: Get Data Count Fail:(BadValue) failed on: cmgo-9p1s39zd_0 :: caused by :: unknown operator: $and;      at new CloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:2425:28)     at Object.returnAsCloudSDKError (/var/user/node_modules/wx-server-sdk/index.js:2477:16)     at Object.checkError (/var/user/node_modules/wx-server-sdk/index.js:1260:23)     at Query.<anonymous> (/var/user/node_modules/wx-server-sdk/index.js:1324:41)     at step (/var/user/node_modules/tslib/tslib.js:133:27)     at Object.next (/var/user/node_modules/tslib/tslib.js:114:57)     at fulfilled (/var/user/node_modules/tslib/tslib.js:104:62)     at <anonymous>     at process._tickCallback (internal/process/next_tick.js:188:7)