Thank you! With your hints I successfully compiled the plugins, which are place into:
C:\Development\Qt\5.5\mingw492_32\plugins\sqldrivers
Now I'm facing the common issue of "QMYSQL driver not loaded but available". I read tons of thread about this but I'm asking some clarification about.
I checked the db server is up (from MySQL Workbench I can connect)
in the pro file of my test app I set:
QT += sql
this is my connection code:
QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
db.setHostName("localhost");
db.setPort(3306);
db.setDatabaseName("test");
db.setUserName("root");
db.setPassword("");
qDebug() << db.open();
in the documentation I cannot find the page where are described the requisites, like which libs to link with, etc...
EDIT:
the error is present only in debug mode1 In release it connect successfully! Anyway I have also qsqlmysqld.dll in the plugins folder.