So two of you don't trust Gartner.The citation provided to scold you was written by ex-Gartner people. LOL.
Fact is that Oracle's market share is more than the next 4 offerings put together. Personally I prefer SQL Server but in real life the most recent database I used was MySQL on Linux.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1