Command failed with error 16412: ‘FieldPath field names may not contain ‘.‘.‘ on server 10.21.20.8:2

    problem description
    query interface error: 

    {"errorMessage":
"Command failed with error 16412: 'FieldPath field names may not contain '.'.' on server 10.21.20.8:27019. The full response is { \"ok\" : 0.0, \"errmsg\" : \"FieldPath field names may not contain '.'.\", \"code\" : 16412, \"codeName\" : \"Location16412\" }"}


com.mongodb.MongoCommandException: Command failed with error 16412: 'FieldPath field names may not contain '.'.' on server 10.21.20.8:27019. The full response is { "ok" : 0.0, "errmsg" : "FieldPath field names may not contain '.'.", "code" : 16412, "codeName" : "Location16412" }
    at com.mongodb.connection.ProtocolHelper.getCommandFailureException(ProtocolHelper.java:115)
    at com.mongodb.connection.CommandProtocol.execute(CommandProtocol.java:114)
    at com.mongodb.connection.DefaultServer$DefaultServerProtocolExecutor.execute(DefaultServer.java:168)
    at com.mongodb.connection.DefaultServerConnection.executeProtocol(DefaultServerConnection.java:289)
    at com.mongodb.connection.DefaultServerConnection.command(DefaultServerConnection.java:176)
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:216)
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:207)
    at com.mongodb.operation.CommandOperationHelper.executeWrappedCommandProtocol(CommandOperationHelper.java:113)
    at com.mongodb.operation.AggregateOperation$1.call(AggregateOperation.java:257)
    at com.mongodb.operation.AggregateOperation$1.call(AggregateOperation.java:253)
    at com.mongodb.operation.OperationHelper.withConnectionSource(OperationHelper.java:435)
    at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:408)
    at com.mongodb.operation.AggregateOperation.execute(AggregateOperation.java:253)
    at com.mongodb.operation.AggregateOperation.execute(AggregateOperation.java:67)
    at com.mongodb.Mongo.execute(Mongo.java:836)
    at com.mongodb.Mongo$2.execute(Mongo.java:823)
    at com.mongodb.DBCollection.aggregate(DBCollection.java:1455)
    at com.mongodb.DBCollection.aggregate(DBCollection.java:1418)
    at com.mongodb.DBCollection.aggregate(DBCollection.java:1403)
    at com.linkus.biz.prj.service.impl.PrjDevTaskStatServiceImpl.getPrjDevTaskStatData(PrjDevTaskStatServiceImpl.java:127)
      problem solving
      check the fields in the group. The grouping fields are wrong. The value “joinbiz. Resp” of resp in the group is changed to “resp” 

      "$group":{
	"_id":{
		"prjSys":"$prjSys",
		"prjMod":"$prjMod",
		"resp":"$_joinBiz_.resp",
	},
	"devTasksCount":{
		"$sum":1
	},
	"minPlanEndDate":{
		"$min":"$_joinBiz_.planEndDate"
	},
	"maxPlanEndData":{
		"$max":"$_joinBiz_.planEndDate"
	},
	"planCompletionCount":{
		"$sum":"$planCompletionNum"
	},
	"actualCompletionCount":{
		"$sum":"$actualCompletionNum"
	}      
}

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