first before first of all, I assume the problem exists on Windows platform, because installing appropriate packet on for example Debian is only typing qmysql (or something similar) in Synaptic

than you're facing with the same problem as I do
first of all, yes You need dll file as you posted

this is explained here for example http://www.qtcentre.org/wiki/index.p...ws_using_MinGW

secondly, depeding on your type of Qt installation (static or sharing libs) there are two ways two follow.
By default Qt is installed with sharing, here is the description http://doc.qt.nokia.com/4.7/deployment-windows.html

nevertheless I am convinced that not only qsqlmysql4.dll is required to be attached to executable file, but also libMySQL.dll which can be found in MySql installation folder.

only after I'd added this dll my program reported than it has a valid mysql driver.
using http://www.dependencywalker.com/ I noticed that qsqlmysql4.dll is loaded properly but application can not find libmySQL.dll file

how this can be explained ? I mean, why qsqlmysql4.dll is not enough here ?