In Version 21.2.1.204 (Build 204.1703) there is problem with export data to “excel.xml” format:
If there is an empty field in the column with numeric format in the database, then after export null is replaced by the value 0 in the xml file.
This seriously falsifies the output data.
This is exactly the same problem as reported in 2014: https://community.oracle.com/tech/developers/discussion/comment/12553936
Regards
Marek