Is that an issue with SQL Developer or with Excel?
What does the data look like if you open it in Notepad or Wordpad?
everything we export to excel is sent as a string - you'll need to format the cells once you're in Excel
This is a long standing enhancement request to export numbers as numbers, dates as dates, etc.
Try this :
select cast(10.2 as binary_double) bin_dou, cast(10.2 as number) as num from dual ;
If you export this to excel, you can make calculation on num but not on bin_dou.
this is an sql developer issue or, like Microsft says, a bad feature....
Try exporting to the csv format, then open in Excel and save in xls or xlsx format. That, at least, works fine in Open Office.
SQL Developer 4.0.3 uses Apache POI 3.8 to handle the export. The latest POI beta is 3.11, but not sure if that contains any improvements for processing the binary_double data type.