Splunk Time difference search

[Sirius27]

I have two results of servers list as per last 30 days and last 12 hrs. I want to compare and find out which servers are not reporting in 12 hrs list. What can be the query for it.
Little new in Splunk.

[Sirius_27]

Hi,
That worked wonderfully, but I'm not getting what type of output is coming lastreport as  some 10 numbers of digit is coming in it.

[ITWhisperer]

lastreport will be an epoch time i.e. the number of seconds since the beginning of 1970. Use strftime to format how it is displayed

| fieldformat lastreport=strftime(lastreport,"%Y/%m/%d %H:%M:%S")

[ITWhisperer]

| stats latest(_time) as lastreport by server
| where now()-lastreport > 12*60*60