I have two different indexes in kibana and both have a common ID say CASE_ID. I want to see how many CASE ID from index 1 matches with CASE ID in index 2
Based on the limited information in your post, I don't think this is possible. But maybe if I can understand your situation in more detail I can help come up with a solution. Can you share an example of the documents in each index? How are the indexes named?
This is a join, which Elasticsearch and Kibana cannot do.
You would need to run two queries, one to grab all the id's from the first index, and then query them in the second index.