How to exclude search query results from base search

[barunbiswas]

I have file processing events with 2 stages - X & Y. I want to get filenames which have gone through X but not Y. I am unable to do so. Could you please advise?
I can list filenames with X stage or Y stage as below

index=test stage=X | stats values(filename)
index=test stage=Y | stats values(filename)

[somesoni2 · Accepted solution]

Try like this

index=test stage=X OR stage=Y | stats values(stage) as stages by filename | where mvcount(stages)=1 AND stages="X"

Basically select rows for both stages, generating list of stages each filename has gone through and finally, selecting only events which went though single stage which is "X".