Mongo 错误：聚合"unknown top level operator: $completed_on"

Question

我正在尝试用Mongo执行聚合操作，如下所示：

db.inbound_documents.aggregate([{"$match": 
{"$completed_on": 
{"$gte":'2018-05-19 00:00:00',
"$lte":'2017-05-19 00:00:00'}}},
{"$group":
{"_id":"$completed_by","total":{"$sum":1}}}])

completed_on在模式中可用，但我不明白它导致该错误的原因。

Answer 1

只需在完成前删除$sign_on:

db.inbound_documents.aggregate([
{"$match": 
{"completed_on": 
{"$gte":'2018-05-19 00:00:00',
"$lte":'2017-05-19 00:00:00'}}},
{"$group":
{"_id":"$completed_by","total":{"$sum":1}}}])