Function setNullTableEngine

src/Interpreters/InterpreterCreateQuery.cpp:1224–1235

    }

    void setNullTableEngine(ASTStorage & storage)
    {
        storage.forEachPointerToChild([](IAST ** ptr, boost::intrusive_ptr<IAST> *)
        {
            *ptr = nullptr;
        });

        auto engine_ast = make_intrusive<ASTFunction>();
        engine_ast->name = "Null";
        engine_ast->setNoEmptyArgs(true);
        storage.set(storage.engine, engine_ast);
    }

    void setNullDictionarySourceIfExternal(ASTCreateQuery & create_query)
    {