Check this link.
As far as Database supports ODBC and OLEDB connections, qlikview can connect to them.
Thank you both for the quick response.
I'm aware that Greenplum and Oracle databases are supported by QlikView.
My question, however, is a little bit different: how to check if QlikView version xx is compatible with Greenplum Database version yy or Oracle Database version zz.
This is a common question when starting a new project or planning an upgrade.
Other software products provide a compatibility matrix in order to answer these kind of questions.