I cannot say much about the license, and I'm not an expert in database programming. But I have bad experience installing MySQL.
Some years ago, my client wanted to install UniCenta, an open source POS system. UniCenta itself supported many well-known databases. The first choice in my head was MySQL, well ... I chose it because I heard a lot about it.
I downloaded and tried to install MySQL on the client's computer, a Windows 7 system. It said it requires dot net version xxx. I checked the computer, the system only had version 3.5 installed. So I tried the older version of MySQL that can run on dot net 3.5. Unfortunately, it said it requires certain version MS VC++. So I tried to install that MS VC++. Yet I couldn't install it, because that required the Windows to update to the newer service pack.
I gave up. After doing some research on the web, they said MariaDB can be used as a drop-in replacement for MySQL. Because MariaDB is a fork of MySQL, I didn't think I would have better luck. Surprisingly to me, I could install MariaDB on the first attempt.
That was my story installing MySQL. My first try and I believe that would be my last.