db.collection('codelist').aggregate().lookup({

from: 'patroltime',

localField: 'code',

foreignField: 'code',

as: 'timelist',

}).sample({

size: 2

}).sort({

createdtime: 1

}).end().then(res2 => console.log(res2))

.catch(err => console.error(err))

查询代码是这样的