We've written a GUI application. Its command-line options are like those in the mysql client. Its graphic features are an SQL-statement text editor and a scrollable SQL result set. It runs on Linux now and we believe it could be ported to other platforms.
Here are four screenshots.
The startup is as non-GUI as can be -- in fact it gets options from the command line, or from my.cnf, the same way that the mysql client does. Wherever it seemed reasonable, we asked: What would mysql do?
The statement (at the bottom of the screenshot) has the usual GUI features for editing, and has syntax highlighting -- comments are green, reserved words are magenta, and so on.
Here the result is appearing in a grid. The second column is long so it's on multiple lines with its own scroll bars.
Finally, here's the same result after fooling around with cosmetics -- the colours and fonts for each section of the screen are resettable via menu items, and the column widths can be changed by dragging.
The program is written in C++ and uses Qt. Qt is available on many operating systems including Mac and Windows but we only tried Linux. The license is GPL version 2. The status is alpha -- there are bugs. Source and executable files can be downloaded from https://github.com/ocelot-inc/ocelotgui.