How to use NOT-EXISTS in SPLUNK ?

[Real_captain]

Hi 

I want to create a search to find all the events for which last row exists but there is atleast 1 row missing. Example is attached below : 

Splunk Query : 

`macro_events_prod_gch_comms_esa` 
gch_messageType="Seev.047*" host="p*" gch_status="*" NOT"BCS" | table BO_PageNumber,BO_LastPage,gch_status
|rename BO_PageNumber as PageNo , BO_LastPage as LastPage , gch_status as Status
| sort by PageNo

Requirement is find all the events for which LastPage as True exists and there is atleast 1 row missing with PageNo  less than the PageNo of row with  LastPage as True.  

[ITWhisperer]

| streamstats count
| where PageNo != count