Where Not Exists()

[olivetwist]

I am trying to improve load times and have been updating code to allow for efficiency. one of the changes i was making is in regards to the Exists() function. my current script looks like this:

LOAD
    test_ID,
    test_ACTIVITY_TS,
    test_ACTIVITY_TYP_CD
FROM $(WorkflowPath)\test.QVD (qvd)
where test_SYSTEM_CD <> 'CWF';

and this works, but when I change "where test_SYSTEM_CD <> 'CWF';" to "where not exists(test_SYSTEM_CD,'CWF');" it returns 0 results. this would probably only save me a few seconds, but i am more interested in why this wouldn't work.

Thanks in advance.

[Anonymous]

Good to know.  Thanks.

Was the load still optimized that way?

[olivetwist]

Yes it was. shaved 1.5 min. every little bit helps.