Build and link MySQL plugin (Qt6 - Qt 6.0.0 + 5.15.2, MySQL 8.0.22, Visual Studio 2019 with Qt Visual Studio Tools 2.6.0.7) - step by step 64bit

deleted414

Hey!
Just a small note; this is my first post here and I'm very new to Qt.
Just a small note2; I was trying to build whole Qt so a part of the steps might not be necessary, but if you get errors try doing every step (aka. random sh*t goes brrrrrrrrr).

So, by following this guide, I managed to get Qt 5.15.2 working perfectly (for me) but barely and I seem to not be able to do the same with Qt 6.0.0. For Qt5 and Qt6, my steps are the same:
I have installed MySQL (community, NOT web-community), Python2 (Windows x86-64 MSI installer), LLVM (I went with "Windows snapshot builds" - 64bit) and Perl64 (Active Perl 5.28).
Python, Perl and LLVM are installed in "C:\"
MySQL was installed in "C:\Program Files", so I copied "include" and "lib" folder from "C:\Program Files\MySQL\MySQL Server 8.0" to "C:\MySql".

Using MaintenanceTool.exe I installed Qt 5.15.2 and 6.0.0 to "C:\Qt".

System PATH variable contains following (important-ish parts, change Qt version as needed):

C:\Python27
C:\Python27\Scripts
C:\Perl64\bin
C:\Qt\6.0.0\msvc2019_64\bin
C:\Qt\Tools\mingw810_64\bin
C:\Qt\Tools\CMake_64\bin
C:\LLVM\bin
C:\MySql\lib
C:\MySql\include
C:\Qt\6.0.0\Src\qtbase\bin

And a new variable LLVM_INSTALL_DIR:

C:\LLVM

Tip: you can find Environment Variables by going Settings>System>About>Advanced system settings and there you'll see a Environment Variables... button, or do a google search.

To build the plugin I have these 3 scripts:

inject_vcvarsall.bat

@echo off
cd "c:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build"
vcvars64.bat
echo on

vcvarsall-qt_src.bat

start cmd /k "inject_vcvarsall.bat & cd /d "C:\Qt\6.0.0\Src" & start ."

vcvarsall-driver_src.bat

start cmd /k "inject_vcvarsall.bat & cd /d "C:\Qt\6.0.0\Src\qtbase\src\plugins\sqldrivers" & start ."

The inject_vcvarsall.bat will run vcvars64.bat script that will setup everything needed for building. vcvarsall-qt_src.bat and vcvarsall-driver_src.bat just open a cmd and targeted folder.
The only thing that changes in those scripts are Qt versions (6.0.0 to 5.15.2).

In "C:\Qt\15.5.2\Src" cmd (vcvarsall-qt_src.bat) (the picture shows 6.0.0 but you can just change it as I mentioned) you run following command:

configure -confirm-license -opensource -sql-mysql MYSQL_INCDIR="C:/MySql/include" MYSQL_LIBDIR="C:/MySql/lib"

Give it a bit of time and it should start checking for different things on your computer. To see if it has detected MySQL, after it's done checking, search for "Qt Sql Drivers:" under "Build options" section:

If MySQL says yes (like in the picture above), congrats, it detected your MySQL.

If it gives you error: ERROR: Feature 'sql-mysql' was enabled, but the pre-condition 'libs.mysql' failed., it probably couldn't detect MySQL. Make sure that MYSQL_INCDIR ("C:/MySql/include") folder contains mysql.h and that MYSQL_LIBDIR ("C:/MySql/lib") folder contains libmysql.lib and libmysql.dll (reference).
Those files are in "C:\Program Files\MySQL\MySQL Server 8.0" and not in "C:\Program Files\MySQL\Connector C++ 8.0" which is weird because I would think that I need to connect to a database and not like run a server with my app or something.
But nevertheless it works this way.

Now you can close that window and run vcvarsall-driver_src.bat.
In opened cmd, run following commands (reference):

qmake -- MYSQL_INCDIR="C:/MySql/include" MYSQL_LIBDIR="C:/MySql/lib" MYSQL_PREFIX="C:/MySql"
nmake sub-mysql
nmake install

After you ran the last command it should be done.

Now. I went through all the steps from above for 5.15.2 and 6.0.0 version, but when I build my application for Qt 5.15.2, it runs ok, but when I target Qt 6.0.0, it gives me this error:

QSqlDatabase: QMYSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QODBC QPSQL
QSqlDatabase::lastError(): Driver not loaded Driver not loaded

The code of my simple application:

#include <QtCore/QCoreApplication>
#include <QtSql>
#include <QtCore>

#include <iostream>

int main(int argc, char* argv[]) {
    QCoreApplication a(argc, argv);

    QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL");
    db.setHostName("127.0.0.1");
    db.setUserName("root");
    db.setPassword("Root_Pass1023");

    db.setDatabaseName("users");

    if (!db.open())
        std::cout << "QSqlDatabase::lastError(): " << db.lastError().text().toStdString() << std::endl;
    else
        std::cout << "YAY" << std::endl;

    db.close();
    return a.exec();
}

NOTE:

configure -confirm-license -opensource -sql-mysql MYSQL_INCDIR="C:/MySql/include" MYSQL_LIBDIR="C:/MySql/lib"

Command for 6.0.0 is now:

configure -confirm-license -opensource -sql-mysql