Avoid deprecated QVariant::Invalid, use the constructor instead.
This is about the following warning:
/tmp/tipp10/sql/trainingsql.cpp:395:26: warning: 'Invalid' is deprecated: Use QMetaType::Type instead. [-Wdeprecated-declarations]
return QVariant::Invalid
The QVariant
constructor without any arguments constructs an invalid variant, see here https://doc.qt.io/qt-6/qvariant.html#QVariant