Rename mysql table if exist if not create a new one

Question

Currently I'm trying to create a new table using mysqli. If the table 'default' exist rename it as the current date and time and if not exist create a new table called default.I get date and time from a previous php page that contains current date and time in plain text without / , - , :. How can I do it using mysqli ?

$bk_time=$_POST['system_clock']."backup";
$conn = new mysqli($db_hostname, $db_username, $db_password);
if (mysqli_connect_errno()) {
  exit('Connect failed: '. mysqli_connect_error());
}
//check default exist
$sql = "SHOW TABLES FROM `descript`.`default`;";
if ($conn->query($sql) === TRUE) {

  $sql. = 'RENAME TABLE `default` TO `$bk_time`';
  echo 'exist';
}
else {
 echo 'not exist ';
 $sql. = 'CREATE TABLE `descript`.`default`';
}
mysqli_autocommit($conn, false);
mysqli_query($conn, $sql);

Answer 1

I suggest using stored procedures:

1. To check if table exists
2. To rename table

The first one would be something like the following

IF EXISTS (
(SELECT * FROM information_schema.TABLES
    WHERE TABLE_SCHEMA = DATABASE()
    AND TABLE_NAME = _tableName))
    THEN SET _result = 0;
ELSE
    SET _result = 1;
END IF;