Need a easier way to include non-null values in jira

I tried raising my concern with my colleague (Sthanunathan for JSP-164449) , however my idea did not get conveyed correctly.

Given that Jira is used by functional tester who do not have to be masters in SQL I suggest that when JSQL gets a query like

select * from jiraissue where FixedVersion!= 'Version2.4.0';

-where FixedVersion can take in null values - jira should internally convert it to

select * from jiraissue where isNull(FixedVersion,-1) != 'Version2.4.0';

I tried this

key in (RETT-2236, RETT-2595) AND isnull(fixversion,-1) != RETT-Backlog

And got the below exception:

Error in the JQL Query: 'isnull' is a reserved JQL word. You must surround it in quotation marks to use it in a query. (line 1, character 431)

I have a work around, as suggested by you,
key in (RETT-2236, RETT-2595) AND (fixversion != RETT-Backlog OR fixVersion is EMPTY)

but the problem is that the user does not have the schema to always know whether its a null field OR not.

Hence what I request is:
If there is a query like this from the front end:
select * from jiraissue where FixedVersion!= 'Version2.4.0';

-where FixedVersion can take in null values - always convert it internally to

select * from jiraissue where isNull(FixedVersion,-1) != 'Version2.4.0';