为什么这个CREATE TABLE查询不起作用

    $sql = "CREATE TABLE tickets
    (
    ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
    Name VARCHAR(32),
    Email VARCHAR(40),
    Subject VARCHAR(40),
    Subject TEXT(500),
    open VARCHAR(10)
    )";

$con->query($sql);

Why doesnt the MySQLi query above work? I have succesfully established connection with the database

You have 2 Subject fields. Rename one of them:

$sql = "CREATE TABLE tickets
(
ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
Name VARCHAR(32),
Email VARCHAR(40),
Subject VARCHAR(40),  // HERE
Subject TEXT(500),   // HERE
open VARCHAR(10)
)";

You have a duplicate column which is Subject.

Schema Creation Failed: Duplicate column name 'Subject'

Rename one of your two columns, for example :

 $sql = "CREATE TABLE tickets
        (
        ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
        Name VARCHAR(32),
        Email VARCHAR(40),
        Subject VARCHAR(40),
        Subject_text TEXT(500),
        open VARCHAR(10)
        )";

 $con->query($sql);

You can use this website http://sqlfiddle.com/ for SQL tests :)