qt_mysql_driver ships prebuilt QMYSQL plug-ins for the Qt versions you cannot compile

The error, and why it happens at all

The whole repository is organised around one runtime error. When you try to connect to MySQL or MariaDB using Qt without the necessary plug-in, Qt prints:

 QSqlDatabase: QMYSQL driver not loaded
 QSqlDatabase: available drivers: QMYSQL

The second line is the confusing part. The driver appears to be listed as available and yet is not loaded, which is a contradiction that sends people looking in the wrong place. What it actually means is that Qt found the QMYSQL plug-in entry but could not load the shared library behind it, usually because the file is missing, is in the wrong directory, or was built against a different Qt.

The root cause is a licensing and distribution decision. Since the Qt Company cannot provide qsqlmysql.dll or libqsqlmysql.so in binary form, you have to build it on your own, which the documentation says can be a pain. That is the gap this repository fills.

So the repository is a distribution point for binaries that Qt itself will not ship, plus a written procedure for producing them. The primary language is not even recorded as one, since the artefact is a compiled C++ plug-in rather than a source project, and the topics are cpp, dll, mysql, mysql-library, qsqldatabase, qt5, qt6 and sql-driver.

The version pairing rule, which is the thing to get right

The documentation is emphatic about this, and the emphasis is the whole point of the project.

You have to match your Qt version and compiler, Microsoft Visual C++ or MSVC, or MinGW, exactly. The example given is that if you use Qt 6.4.2, you cannot use driver version 6.4.1 or 6.4.3.

That example is worth reading carefully, because it rules out the obvious shortcut. A developer who sees a driver for 6.4.x and their Qt is 6.4.2 might reasonably assume the 6.4 line is close enough. It is not. The plug-in is a shared library that links against the Qt libraries it was compiled with, and the loader expects an exact match of the Qt version it was built for.

The release naming follows the Qt version rather than the driver's own version, and the tags are qmysql_6.12.0 from 2026-10-02, qmysql_6.11.2 from 2026-08-19 and qmysql_6.11.1 from 2026-05-14. The current Qt 6 download is the 6.12.0 one, and the documentation notes that for Android there is a third party repository instead, since the Android case is handled by a separate project.

The last push was on 2026-10-02, the same day as the newest tag, so the release line is current.

Deployment is two copy operations

The deployment instructions are short and they are the part most people get wrong, because the driver file alone does not make a working connection.

The first step is to copy the driver plug-in into a sqldrivers subdirectory of the application directory, or the build directory while you are developing. The documentation is specific about which file for which build: qsqlmysql.dll for a release build, and for MSVC the debug build is qsqlmysqld.dll, while for MinGW the debug build adds qsqlmysql.debug alongside qsqlmysql.dll.

The second step is to copy the MySQL library and the OpenSSL libraries. That means libmysql.dll for MySQL, plus the libcrypto and libssl OpenSSL libraries, taken from the zip file or from the MySQL and FireDaemon download pages. These go into the application directory, or more generally into any directory that is registered in the PATH environment variable.

So the dependency chain is three files or sets of files: the Qt SQL driver plug-in in sqldrivers, the MySQL client library, and the OpenSSL libraries. The second and third are not Qt's responsibility at all, they are what the driver links against, and forgetting them produces a driver that is present but will not load, which is the same error as before.

The screenshots in the documentation show the two directory layouts, which is the fastest way to check your own installation against a working one.

Building it yourself with Qt 6 and CMake

The build recipe is given for Windows with both compilers, and it is the same shape in both cases: point the PATH at the CMake, compiler and Ninja tools, change into the Qt source tree for the SQL driver plug-ins, run the Qt-provided CMake wrapper with the MySQL paths and an install prefix, then build and install.

For MSVC the prerequisites are the MSVC compiler from the Visual Studio 2022 setup, then Qt including sources with CMake and Ninja from the Maintenance Tool, then the MySQL library. The sequence is:

set PATH=%PATH%;C:\Qt\Tools\CMake_64\bin;C:\Qt\Tools\Ninja
C:
cd C:\Qt\6.9.2\Src\qtbase\src\plugins\sqldrivers
call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"
call C:\Qt\6.9.2\msvc2022_64\bin\qt-cmake.bat -G "Ninja Multi-Config" . -DMySQL_INCLUDE_DIR="C:\Users\Administrator\Documents\qt_creator\lib\libmysql\include" -DMySQL_LIBRARY="C:\Users\Administrator\Documents\qt_creator\lib\libmysql\lib\libmysql.lib" -DCMAKE_INSTALL_PREFIX="C:\Qt\6.9.2\msvc2022_64" -DCMAKE_CONFIGURATION_TYPES=Release;Debug  -DQT_GENERATE_SBOM=OFF
ninja
ninja install
pause

For MinGW the prerequisites are Qt including sources with CMake and MinGW from the Maintenance Tool, and the MySQL library. The same steps run with a different Qt toolchain path, a MinGW compiler path and the MinGW install prefix, and the toolchain path includes the MinGW 13.1.0 64 bit directory:

set PATH=%PATH%;C:\Qt\Tools\CMake_64\bin;C:\Qt\Tools\mingw1310_64\bin;C:\Qt\Tools\Ninja
C:
cd C:\Qt\6.9.2\Src\qtbase\src\plugins\sqldrivers
call C:\Qt\6.9.2\mingw_64\bin\qt-cmake.bat -G "Ninja Multi-Config" . -DMySQL_INCLUDE_DIR="C:\Users\Administrator\Documents\qt_creator\lib\libmysql\include" -DMySQL_LIBRARY="C:\Users\Administrator\Documents\qt_creator\lib\libmysql\lib\libmysql.lib" -DCMAKE_INSTALL_PREFIX="C:\Qt\6.9.2\mingw_64" -DCMAKE_C_COMPILER="gcc.exe" -DCMAKE_CXX_COMPILER="g++.exe" -DCMAKE_CONFIGURATION_TYPES=Release;Debug   -DQT_GENERATE_SBOM=OFF
ninja
ninja install
pause

Two details in those commands are worth noticing. The source directory is the Qt source tree itself, at qtbase src plugins sqldrivers, so you need the Qt sources installed rather than only the binaries. And the configuration types include both Release and Debug, which is what produces the two plug-in files the deployment step expects.

What the repository actually contains

The repository is minimal, which is consistent with a project whose output is release artefacts rather than a buildable source tree.

At the top level there is a README.md, a .gitignore, a .github directory, and two licence files, LICENSE.LGPLv21 and LICENSE.LGPLv3. That pair of licences is the point: the Qt SQL driver plug-ins are built from Qt's own source, which is licensed under the LGPL, and both the LGPL 2.1 and the LGPL 3 texts are included. The platform is recorded as a custom licence that the hosting service cannot classify, but the presence of the two LGPL files in the tree says plainly where the underlying code comes from.

So the prebuilt binaries are third-party LGPL code repackaged, and the licences travel with them. Anyone distributing a Qt application with a bundled driver is the one who has to think about the LGPL obligations, and the fact that the licences are in the repository is a helpful starting point.

The project is maintained by a single person, thecodemonkey86, and the README carries a PayPal donation link with a note that donations are welcome. The releases page is where the binaries live, and the newest Qt 6 download is linked directly from the readme.

Editorial conclusion

Adopt this repository if you hit the QMYSQL driver not loaded error on Windows or Linux and you would rather download a matching plug-in than build Qt from source. Do not adopt it without checking the exact version pairing, because a driver built for a neighbouring Qt version will not load. Before you download anything, check three things: your exact Qt version, down to the patch level, the compiler you built Qt with, since MSVC and MinGW need different binaries, and whether you also need the MySQL client library and the OpenSSL libraries copied next to your executable, because the driver alone is not enough to connect.

Frequently asked questions

Official sources

1. Issues
2. README
3. Releases
4. thecodemonkey86/qt_mysql_driver on GitHub