与MariaDB的PHP代码中的MySql错误

When I try to create new entries to a mysql table and bring variables from one php file to another with start_session() I get the following error:

Error: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ')' at line 2

My code looks like this:

session_start();  

$servername = "xxx";  
$username = "johndoe";  
$password = "password";  
$dbname = "databese";  

try {
    $conn = new PDO("mysql:host=$servername;dbname=$dbname", 
                    $username, $username, $password);

First of all there is nothing in line 2.

session_start() was working before with the same file when I created the table.

Any Idea?

And when you locate the query, look at the end of it. I'll guess you have an extra right paren.