Summary

Currently , JIRA only allow {{ ~ }} and {{ !~ }} operator for comment field .
If use comment ~ ABC
It will display issue that contains ABC word in any comments in the issue .
If use comment !~ ABC
It will display issue that does not contains ABC word in any comments in the issue .

User expected to have query that will display issue , as long as it have/not ABC word , it will not display the issue .

Steps to Reproduce

1. Create a JIRA ticket (let's say ticket ID is ABC-1)
2. add two comments to above ticket. Sample comments are given below;
   Comment 1: RCA
   Comment 2: test
3. Search above ticket using following JQL to search above ticket

   comment !~ RCA

Expected Results

No issue will display

Actual Results

ABC-1 will display

Workaround

To filter issue without "RCA" comment :-

1. Save Filter1 as below query :-

   comment !~ RCA
   

2. Then , filter using below query :-

   not filter = "Filter1"
   

But , do note it only work for issue ticket that have multiple comment . It will not work for issue that have 1 comment .