getList:function(){

    let x = this.data.total

    let y = this.data.pageSize

    let old_data = this.data.shopList

    wx.cloud.callFunction({

      name:'twotableQuery',

      data:{

        collection:'release_Data',

        from:'user',

        localField:'_openid',

        foreignField:'_openid',

        as:'seller_id',

        match:{

          buyer_openid:app.globalData.openid,

          buy_status:"交易中"||"交易成功" //我想在这用或，意思是buy_status="交易中"或buy_status="交易成功"

        },

        sort:{time:-1},

        x:x,

        y:y

      },

      success:res=>{

        console.log(res)

        x=x+y

        this.setData({

          shopList:old_data.concat(res.result.list),

          total:x

        }) 

      }

    })

  }

这是云函数代码

const cloud = require('wx-server-sdk')

cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV }) // 使用当前云环境

const db = cloud.database()

var $=cloud.database().command.aggregate

const _ = db.command

// 云函数入口函数

exports.main = async (event, context) => {

  return await db.collection(event.collection).aggregate()

  .match(event.match).sort(event.sort).limit(event.y).skip(event.x)

  .lookup({

    from:event.from,

    localField: event.localField,

    foreignField: event.foreignField,

    as: event.as

  })

  .end({

    success:function(res){

      return res;

    },

    fail(error){

      return error;

    }

  })

}