我没有得到这个代码中的错误，“注意：未定义的变量：第27行的C：\ xampp \ htdocs \ w3s \ createtablepdo.php中的sql”

Question

I don't understand what is wrong with the code below. Everything seems fine but I'm still getting a notice:

Notice: Undefined variable: sql in C:\xampp\htdocs\w3s\createtablepdo.php on line 27 " and error could not find driver.

 <?php
    $servername="localhost";
    $username="root";
    $password="";
    $dbname="mysql";
    try
    {
        //creating connection
        $conn = new PDO("mysqli:host=$servername;dbname=$dbname",$username,$password);

        //checking exception
        $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
         // sql to create table
            $sql = "CREATE TABLE MyGuests (
            id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY, 
            firstname VARCHAR(30) NOT NULL,
            lastname VARCHAR(30) NOT NULL,
            email VARCHAR(50),
            reg_date TIMESTAMP
            )";
        //use exec cos no result are returned
        $conn->exec($sql);
        echo "table MyGuests created succesfully";
    }
    catch(PDOException $e)
    {
        echo $sql . "<br>" . $e->getMessage();
    }

    $conn = null;
?>

Answer 1

I guess you are following this tutorial for creating new table using PDO. If you see the code on the link carefully, you will need to change the line

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

to following

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

See this link for PDO Connections and Connection management