base0 | Binary encoding inspired by base1

You are creating temporary tables - temporary tables only exist for the extent of the session - since every exec is in a unique session AND DIFFERS from the session you are running the procedure in the temporary tables are never available to the session in which you are running the procedure...

or as the manual says 'You can use the TEMPORARY keyword when creating a table. A TEMPORARY table is visible only within the current session, and is dropped automatically when the session is closed.' https://dev.mysql.com/doc/refman/8.0/en/create-temporary-table.html

Consider creating permanent tables and deleting them when you are done.

This is a somewhat dangerous pattern in general. It's possible to keep things strictly valid, but in the example shown, it's actually the conversion from Base1* to AnotherClass* which is not allowed by the Standard.

[class.cdtor]/2 gives some restrictions on converting a pointer from derived class to base class:

To explicitly or implicitly convert a pointer (a glvalue) referring to an object of class X to a pointer (reference) to a direct or indirect base class B of X, the construction of X and the construction of all of its direct or indirect bases that directly or indirectly derive from B shall have started and the destruction of these classes shall not have completed, otherwise the conversion results in undefined behavior.

When the initializer "this" for the Base0 subobject is evaluated, the construction of Derived has started, but the construction of its Base1 subobject has not started. But since there are no other classes in the inheritance tree which derive from Base1, the Derived* to Base1* conversion is okay. Converting this to a pointer to grandparent class would not be okay if the parent class constructor hasn't started; if the grandparent class is a virtual base class, the conversion isn't allowed until the last intermediate class which inherits it has started construction!

At first, that converted pointer points at an object whose (non-trivial) construction has not yet started, so it's subject to the restrictions in [class.cdtor]/1 and [basic.life]/6. Mostly, you can't get at any of its base class subobjects or members yet. Copying that pointer, without any further implicit base class pointer conversions, is almost all you can legally do with it. So the example's implicit conversion from Base1* to AnotherClass* results in undefined behavior. It would be okay, though, if the anotherObj member had exactly the same type Base1*.