ref #9436
Currently EPHEMERAL column requires an explicit default value provided on CREATE TABLE - we can allow implicit default there

auto drop_context = Context::createCopy(context);
                InterpreterDropQuery interpreter(drop_ast, drop_context);
                interpreter.execute();
            }
            else
                throw Exception(storage_already_exists_error_code,
                    "{} {}.{} already exists", storage_name, backQuoteIfNeed(create.getDatabase()), backQuoteIfNeed(create.getTable()));
        }
        else if (!create.attach)
        {
            
            try
            {
                database->checkMetadataFilenameAvailability(create.getTable());
            }
            catch (const Exception &)
            {
                if (create.if_not_exists)
                    return false;
                throw;
            }
        }
        data_path = database->getTableDataPath(create);
        if (!create.attach && !data_path.empty() && fs::exists(fs::path{getContext()->getPath()} / data_path))
            throw Exception(storage_already_exists_error_code,
                "Directory for {} data {} already exists", Poco::toLower(storage_name), String(data_path));
    }
    else
    {
        if (create.if_not_exists && getContext()->tryResolveStorageID({"", create.getTable()}, Context::ResolveExternal))