I want to run a search but can't figure out what's the difference when I make changes to it using the 'where' clause
What's the difference between
...base search extension!=NULL|where Module="previewservice" | chart count by Module, FinalState
...base search |where Module="previewservice" AND extension!=NULL| chart count by Module, FinalState
The first one produces an output while the second one does not 😕
Your first search string is the more efficient of the two, as it's best to exclude as early as possible. However, to make the second example work, replace
This is because where uses eval expressions, one of which is the function isnotnull. In your second example extension!=NULL is actually interpreted as <fieldA> is not equal to <fieldB> (where <fieldB> is a non-existent field called NULL).
For reference, see the documentation on Informational Functions (http://docs.splunk.com/Documentation/SplunkCloud/6.6.1/SearchReference/InformationalFunctions)
<fieldA> is not equal to <fieldB>
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Salut! You Sir are a true genius!