I have same problem and stacked long time at here .
Now I have use the QT5.10.1 maybe can get succeed.
I have no time on it, but i will try it from July.
If you have any new progress could you update on this topic?
I'm just realizing that what I was trying to do was maybe nonsense : I was trying to pass on to the mysql server a value for the client on which my Qt program is running i.e. I was trying to "deceive" the server. And I could understand then that there would be no such method in QSqlDatabase (and that you couldn't understand my question initially).
download the Qt Sources, e.g current the sources available are qt-everywhere-opensource-src-5.5.1, After extracting
then make sure you call qmake from Qt5.5, for this purpose you can type the complete path of the qmake.
then use make and make install.
I hope it will help you.