Using Kibana to Execute Queries in ElasticSearch using Lucene and Kibana Query Language – BMC Software | Blogs
Boolean field accepts an empty string, does not index as `null` · Issue #61038 · elastic/elasticsearch · GitHub
Elasticsearch - Painless is Really Painless - GeeksforGeeks
Filter document with not null value in Kibana Discover. Should I use "exist", but it still return me docs with empty field - Kibana - Discuss the Elastic Stack
Custom Fields and ElasticSearch | Diagram
Failed to parse field of type in document with id ''." - Common causes and quick fixes