Unsolved QMYSQL driver not loaded in os windows

[javad935]

این ارور چطوری رفع کنم ؟
QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QMYSQL QMYSQL3 QODBC QODBC3 QPSQL QPSQL7

[JonB]

@javad935
Google for: QSqlDatabase: QMYSQL driver not loaded
There are plenty of answers.
I forget what it is for Windows, but you have to install some kind of libmysql.dll to allow it to load QMYSQL driver.

[LFBuildAMountain]

I have add C:\mysql\mysql-5.7.21-winx64\lib into path variable. but don't work!