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Why is ISNULL functionality not working?

Keerthi
Path Finder

Keerthi_0-1681721858028.png

I am trying to get the data only when my lastlogon(field name) is Null. but the above query is still giving me data for both Null and non Null values.

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woodcock
Esteemed Legend

Fields are case sensitive and also sometimes "empty" (i.e. == "").  You can check for both like this:

(isnull(LASTLOGON) OR LASTLOGON=="")

ITWhisperer
SplunkTrust
SplunkTrust

Field name are case-sensitive - try this

| where isnull(LASTLOGON)
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