I found it once, but lost it...

Database GUI? Really? There is no graphical user interface to the database as such, but you can see the results of your database in the Collection Browser, which is default on the left pane of Amarok.
Editing the database by hand is not a good idea, and I fail to see a use-case that would be needed by most users. Can you elaborate, please?

The GUI for making queries of the database.

It WAS there! Honestly!

erm, no? I know Amarok since years, there is no graphical user interface to query the database, and never was, at least not since I use it, and that is since 1,x times.
Are you sure you are not mixing that up with the filter editor for the collection Browser? That is not a database GUI

Maybe it was the collection filter. But I ran a"query" that was: played more than 1 time, 2 times, 3 times, 4 times, 5 times and got back a list of those songs.

yes, but that is just a filter for the Collection Browser, which displays all your music sources. It is not a mysql database GUI, as you can't use all SQL queries.

Thanks!!