From the FAQ at http://wiki.gnucash.org/wiki/FAQ
Q: How can I export data?
- A: There’s an XSLT at http://xslfactory.free.fr/ which can transform a gnucash XML file to a big gnumeric spreadsheet. The Workbook will contain several sheets; One with all the accounts, a diary with all the transactions, and on sheet by account with all the transactions. Prior to running the transform, you’ll need to edit the gnucash XML file (preferably a copy of it) to include xmlns data. (Note however that as at 24th Apr ’04 it doesn’t include support for business objects, eg: invoices.)
- There is also http://gnucashtoqif.sourceforge.net/ which is a Java program that can transform a gnucash XML file to a QIF file.
- As of the 2.0 release series, the GnuCash data file may be compressed. Just gunzip the data file to see the raw XML. Alternatively you can change the saving state of the GnuCash data file by going to the General tabbed page in GnuCash Preferences dialog box (Edit->Preferences->General) and toggle the compression feature.
- There exist some scripts to move gnucash data into a mysql database