云对象中使用aggregate查不到数据，但是jql查询中可以查到

//=========================下面代码在云对象中获取到为{}空
let currentUid = "0";
const dbJQL = uniCloud.databaseForJQL()
dbJQL.setUser({
uid: currentUid,
role: ['admin'],
})
let queryInfo = dbJQL.collection('chat-message').aggregate()
.sort("create_date, ase")
// .group({
// _id: "$roomId",

//  message: dbJQL.command.aggregate.first('$message'),  
//  state: dbJQL.command.aggregate.first('$state'),  
//  sendUid: dbJQL.command.aggregate.first('$sendUid'),  
//  sendNickName: dbJQL.command.aggregate.first('$sendNickName'),  
//  lastMessageDate: dbJQL.command.aggregate.first('$create_date')  
// })  
.limit(20)  
.end()  
console.log("queryInfo:"+JSON.stringify(queryInfo))  

// ===========================下面代码在jql中可以获取到数据两条。

db.collection('chat-message').aggregate()  
.sort("create_date, ase")  
// .group({  
//  _id: "$roomId",  

//  message: db.command.aggregate.first('$message'),  
//  state: db.command.aggregate.first('$state'),  
//  sendUid: db.command.aggregate.first('$sendUid'),  
//  sendNickName: db.command.aggregate.first('$sendNickName'),  
//  lastMessageDate: db.command.aggregate.first('$create_date')  
// })  
.limit(20)  
.end()