SQL Query syntax issues when using variable - php

Question

SQL query "GRANT ALL PRIVILEGES ON name_$DBname.* TO 'name_$DBname'#'localhost'"
Output for this:
Access denied for user 'name'#'localhost' to database 'name_posmechanics'
when written like below - it outputs the variable correctly but..
SQL query "GRANT ALL PRIVILEGES ON name_$DBname.* TO '. 'name_$DBname'#'localhost'. "
error for syntax
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'name_posmechanics'#'localhost'.' at line 1
It shows that when written the way it wants to be, it will ignore my variable, but it did show correctly 'name_posmechanics'#'localhost' when the syntax error is present and shows 'name'#'localhost' whith no syntax errors? why would the variable work referring to the db name but not when refering to the User
I understand there is a issue with permissions at the moment, however I would like to get the syntax error corrected first and then move on the the next issue.
here is the complete code
add_action( 'plugins_loaded', array( 'pos_URL__db', 'init' )); //This will trigger everytime the page is refreshed but only apply if all conditions are met
class pos_URL__db {
public static function init() {
$POS__sys_db = __CLASS__;
new $POS__sys_db;
}
public function __construct()
{
add_action('init', array($this, 'pos__URL_DB'));
}
public function pos__URL_DB()
{
//--------to access the order objects----start-----
$orders = wc_get_orders(array(
'customer_id' => get_current_user_id(),
'return' => 'ids',
));
//add the id of the custom meta field that lies in the order
$meta_data = array();
foreach ($orders as $order_id) {
$meta_data[$order_id] = get_post_meta($order_id, '_engx_text_field_id', true); //get the field value entered by the vendor on checkout
}
//--------to access the order objects-----end-----
if( isset($meta_data[$order_id]) ) { //is the custom field set
//dependencies
$servername = "localhost"; // always the same "localhost"
//$username = $meta_data[$order_id]; //get name of field unique to each user saved from checkout process
$username = "name"; //get name of field unique to each user saved from checkout process
//$password = "testing22"; //passcode for database
$password = 'TestIngTT'; //passcode for database
$DBname = $meta_data[$order_id]; //get name of field unique to each user saved from checkout process
// Create connection
$conn = mysqli_connect($servername, $username, $password);
// Check connection
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
//mysql_connect('localhost','user',password);
//mysql_query("CREATE USER 'username'#'localhost' IDENTIFIED BY 'password';");
//mysql_query("GRANT ALL ON db1.* TO 'username'#'localhost'");
// Create User
//$sql = "CREATE DATABASE . $DBname . "; //Name of NEW Database replace "myDB" with the POS-URL custom field meta value from checkout
//$sql = "CREATE DATABASE testDB"; //Name of NEW Database replace "myDB" with the POS-URL custom field meta value from checkout
$sqlcommands = array(
"CREATE DATABASE name_$DBname",
"CREATE USER 'name_$DBname'#'localhost' IDENTIFIED BY 'TestIngTT!'",
//"GRANT ALL PRIVILEGES ON * . * TO name_$DBname",
"GRANT ALL PRIVILEGES ON name_$DBname.* TO 'garagepo_$DBname'#'localhost'",
//"GRANT ALL ON db1.* TO 'username'#'localhost'"
);
foreach ($sqlcommands as $sql)
{
// Create database
if (mysqli_query($conn, $sql)) {
echo "Database created successfully"; //comment when not needed
} else {
echo "Error creating database: " . mysqli_error($conn); //comment when not needed
}
}
mysqli_close($conn);
}
}//end pos__URL_DB
}//end Class pos_URL__db