troubleshooting Question

Mongodb using last result as the next query input?

Avatar of Steve Wong
Steve WongFlag for Hong Kong asked on
MongoDBJavaScriptJSON
5 Comments1 Solution204 ViewsLast Modified:
I have a mongodb document as below.  I want to return the documents with Maximum CurrentTicks, but since the tick was dynamically generated, I would need to return it to a variable LastTick, but when I try to retireve it in to the next query

First Query:          var LastTick = db.HKMachineStatus_v2.aggregate({$group: {_id : '' , Tick: {$max: "$CurrentTicks"}}})
Second Query:     db.HKMachineStatus_v2.find({"CurrentTicks" : LastTick})

it just return me "Fetched 0 record(s) in 5ms" But there is no result to return.

Then I only run the first Query it did return me the result as the image attached Result_outPut_1.jpg .

So my questions are
1. how to retrieve the Tick's value from LastTick
2. will my second Query success if I run in that way?
3. if not what will be better way to do it?  


below are the mongodb documents sample.

{
    "_id" : ObjectId("580e1f26fa9382133c202a04"),
    "ProcessTime" : "24472016-22:47:58",
    "HostName" : "APPServer",
    "IPAddress" : "192.168.0.1",
    "OS" : " Linux",
    "Status" : "Machine running",
    "CurrentTicks" : "636129460749210826"
},
{
    "_id" : ObjectId("580e1f26fa9382133c202a05"),
    "ProcessTime" : "24472016-22:47:58",
    "HostName" : "APPServer2",
    "IPAddress" : "192.168.0.2",
    "OS" : " Linux",
    "Status" : "Machine running",
    "CurrentTicks" : "636129460749210826"
},
{
    "_id" : ObjectId("580e21e1fa9382133c202d16"),
    "ProcessTime" : "24582016-22:58:57",
    "HostName" : "DC",
    "IPAddress" : "192.168.0.43",
    "OS" : " Windows",
    "Status" : "Machine running",
    "CurrentTicks" : "636129467352901129"
},
{
    "_id" : ObjectId("580e21e1fa9382133c202d17"),
    "ProcessTime" : "24582016-22:58:57",
    "HostName" : "DC2",
    "IPAddress" : "192.168.0.45",
    "OS" : " Windows",
    "Status" : "Machine running",
    "CurrentTicks" : "636129467352901129"
}
Result_output_1.JPG
ASKER CERTIFIED SOLUTION
leakim971
Multitechnician
Join our community to see this answer!
Unlock 1 Answer and 5 Comments.
Start Free Trial
Learn from the best

Network and collaborate with thousands of CTOs, CISOs, and IT Pros rooting for you and your success.

Andrew Hancock - VMware vExpert
See if this solution works for you by signing up for a 7 day free trial.
Unlock 1 Answer and 5 Comments.
Try for 7 days

”The time we save is the biggest benefit of E-E to our team. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange.

-Mike Kapnisakis, Warner Bros