You can edit a JSON document in MySQL with:

• The JSON_SET function that will replace values for JSON paths that exists and add values for the ones that don’t exist.
• The JSON_REPLACE function that will replace values for JSON paths that exists and ignore the ones that don’t exist.

PostgreSQL® offers two types of data types to handle JSON data, JSON and JSONB, you can use the jsonb_set function to remove the null values for JSONB columns.