/qt_mysql_driver

Typical symptom: QMYSQL driver not loaded -> get pre-built Qt SQL driver plug-in required to connect QSqlDatabase to MySQL / MariaDB with QSqlDatabase::addDatabase("QMYSQL"). Download qsqlmysql.dll binaries built from official Qt source code

OtherNOASSERTION

Typical symptom when trying to connect to MySQL / MariaDB using Qt but without the necessary plugin is the runtime error


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

Since the Qt Company cannot provide qsqlmysql.dll / libqsqlmysql.so in binary form, you have to build it on your own, which can be a pain. Here is a build for various Qt versions. Get precompiled qsqlmysql.dll for Windows / libqsqlmysql.so for Linux from releases

Latest Qt version: Download for Qt 6.3.1 here

Deployment

  1. put qsqlmysql.dll / qsqlmysqld.dll in application subdirectory "sqldrivers"
  2. put libmysql.dll (the MySQL library itself) and the OpenSSL v1.1 libraries, libcrypto-1_1 and libssl-1_1, in your application dir

Building from source (Qt6/CMake)

Windows
for MSVC:

Prerequisites:

  1. Install MSVC Compiler (C++ Desktop Toolkit from Visual Studio 2022 Setup)
  2. Install Qt incl. Sources, CMake and Ninja from Maintenance Tool
  3. Install MySQL library, e.g. by using Oracle's Installer or use the zip file from here
set PATH=%PATH%;C:\Qt\Tools\CMake_64\bin;C:\Qt\Tools\Ninja
cd C:\Qt\6.4.0\Src\qtbase\src\plugins\sqldrivers
call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"
call C:\Qt\6.4.0\msvc2019_64\bin\qt-cmake.bat -G "Ninja" . -DMySQL_INCLUDE_DIR="C:\mysql_8.0.29\include" -DMySQL_LIBRARY="C:\mysql_8.0.29\lib\libmysql.lib" -DCMAKE_INSTALL_PREFIX="C:\Qt\6.4.0\msvc2019_64"
ninja
ninja install
call C:\Qt\6.4.0\msvc2019_64\bin\qt-cmake.bat -G "Ninja" . -DMySQL_INCLUDE_DIR="C:\mysql_8.0.29\include" -DMySQL_LIBRARY="C:\mysql_8.0.29\lib\libmysql.lib" -DCMAKE_INSTALL_PREFIX="C:\Qt\6.4.0\msvc2019_64" -DCMAKE_BUILD_TYPE=Release
ninja
ninja install
pause

for MinGW:

Prerequisites:

  1. Install Qt incl. Sources, CMake and MinGW from Maintenance Tool
  2. Install MySQL library, e.g. by using Oracle's Installer or use the zip file from here
set PATH=%PATH%;C:\Qt\Tools\mingw1120_64\bin;C:\Qt\Tools\CMake_64\bin
cd C:\Qt\6.4.0\Src\qtbase\src\plugins\sqldrivers
call C:\Qt\6.4.0\mingw_64\bin\qt-cmake.bat -G "MinGW Makefiles" . -DMySQL_INCLUDE_DIR="C:\mysql_8.0.29\include" -DMySQL_LIBRARY="C:\mysql_8.0.29\lib\libmysql.lib" -DCMAKE_INSTALL_PREFIX="C:\Qt\6.4.0\mingw_64" -DCMAKE_C_COMPILER="gcc.exe" -DCMAKE_CXX_COMPILER="g++.exe"
mingw32-make
mingw32-make install
pause