mysqli_real_string_escape失败了GET

I have a static database connection established in a file which I include as

include_once 'database.inc.php';

named $mysqli.

When I pass a parameter $tbname from a form using $tbname = $_GET['tbname'], and attempt to use $tbname = $mysqli->real_esacpe_string($tbname), it produces identical output to $tbname, including when invalid characters such as /,'" are used in the name.

Based on looking at other questions and proper usage, I cannot find a reason why the string escape should fail. It also fails if a procedural call is used to mysqli_real_escape_string($mysqli, $tbname).

When $tbname is valid and not string escaped by the function, my query

query = $mysqli->prepare("CREATE TABLE $tbname (ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY)") or trigger_error($mysqli->error."[$query]");

works as intended.

1. There is no reason to use this function for escaping a table name, and you should never use it for such a purpose.
2. There is no reason in creating tables from user input, and you should never create tables on the fly, but always have solid and predefined database structure.
3. mysqli_real_escape_string DOES escape these symbols \'". But you should never use it. Instead, you have to use prepared statements