Hi:
I have compile the mysql drivers and connect the mysql server sucessfully , with the help of "http://ieatbinary.com/2011/07/11/how-to-enable-mysql-support-in-qt-sdk-for-windows/" .

at the sixth step as this article show, I have to copy libmysql.dll from mysql installation directory to the c:\windows directory.

But I still have a issue that what's the function of libmysql.dll