PHP/MySQL Checking if user exists: function does not work

Question

** SOLVED **

** I made a stupid typo in the function sanitize. I created her as sanitze. Thank you **

If anybody could help me, I would appreciate it very much. I am learning the database interaction and have a User in my database called 'George'.

To check if he exists I have this function:

function sanitze($data) {
    return mysql_real_escape_string($data);
}

function user_exists($username) {
    $username = sanitize($username);
    $query = mysql_query("SELECT COUNT(`user_id`) FROM `users` WHERE `username` = '$username'");
    // Check the result of the query (COUNT) and return either true or false
    return (mysql_result($query, 0) == 1) ? true : false;
}

And then I am checking the Username with this If statement:

if(user_exists('George') === true) {
    echo 'User exists';
} else {
    echo 'User doesn\'t exist';
} die ();

But I don't get any results. I found this Thread: PHP username check function not working

And I am currently working on it, but haven't found any solution yet.

If anyone knows the answer. It would be great.

Why count? instead of SELECT username FROM users where name = ? ?? — samayo
– samayo, Commented Nov 24, 2013 at 14:35
Check out PDO prepared statements. Even with your sanitize function, this approach still isn't safe. — Niketa
– Niketa, Commented Nov 24, 2013 at 14:37
@Qǝuoɯᴉs Why get the username if you don't want it? The username is already the input for the query. — GolezTrol
– GolezTrol, Commented Nov 24, 2013 at 14:38
write as well. -> ....WHERE username = '" . $username . "'" — Aldi Unanto
– Aldi Unanto, Commented Nov 24, 2013 at 14:38

GolezTrol · Accepted Answer · 2013-11-24 14:36:01Z

2

The function is called sanitze and you call it using sanitize. That's two different spellings.

If you enable error reporting (either in runtime or in your configuration), PHP should show you pretty detailed information about errors like this:

answered Nov 24, 2013 at 14:36

GolezTrol

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2 Comments

Noam Rathaus Over a year ago

I hope this isn't the issue :)

GolezTrol Over a year ago

That happens. If you're new to some specific thing (like databases), you automatically assume that that is where the error must be. One good reason to use error reporting, so you're not in the blind.

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