The latest iteration is actually called 'ActianX', and it's a continuation of Ingres plus support for column-based tables from the 'Vector' product acquired by Actian.
QUEL is still there, but its functionality has been frozen for years and, in terms of bells and whistles, is way behind modern SQL.
If you do want to try it, I had no trouble installing it on my home Ubuntu system a couple of years ago. Ingres is pretty easy to use in some ways. If you want to make a database, you just type "createdb mydatabase" at the command line.
QUEL is still there, but its functionality has been frozen for years and, in terms of bells and whistles, is way behind modern SQL.
If you do want to try it, I had no trouble installing it on my home Ubuntu system a couple of years ago. Ingres is pretty easy to use in some ways. If you want to make a database, you just type "createdb mydatabase" at the command line.