Oracle had 48.8% of the market in 2011, according to Gartner. That was up from 48.2% in 2010. IBM with its DB2 database and Microsoft with its SQL Server databases were 20.2% and 17%, respectively. Thanks to Colleen Graham, a research director at Gartner, I have the rundown:

As you can see, Oracle’s growth was the largest in terms of raw dollars, and second largest in terms of percentage. The largest percentage growth went to SAP/Sybase, which already has Sybase databases and is trying to ramp up its database business further with the SAP HANA in-memory appliance. But its percentage growth is largely because it was starting from a smaller base. Can SAP really be the #2 database vendor by 2015, as it hopes to be? For that to happen, it would have to at least quadruple its database business in the next four years.