Elasticsearch declare field as null

Question

I would like to declare a field to null not with null_value.

Are "" and null equivalent? If I do not write anything to field, will ES set set the null automatically?

Answer 1

If you want the field to be null just don't index it.

"" (empty string) is a non-null value (see the doc), and will be stored in the document (but not in the inverted index).