Viktor Viktor - 1 month ago 5
MySQL Question

Problems with checking for duplicate user in MySQL with php

Im trying to check if the username already exists in the database, but I'm struggling with it. I get an error saying:

Call to a member function bind_param() on boolean in /var/www/public/firsttry/index.php

This is part of my code where I'm trying to implement this:

/*Check for duplicate in DB */
$stmt2 = $mysqli->prepare("SELECT username FROM Users (username, password) WHERE username = ?");

$stmt2->bind_param("s", $username);

$rows= mysqli_num_rows($stmt2);

echo "<script type='text/javascript'>alert('This username is taken!')</script>";

As you can see first I write a prepared statement and try to bind a value into it which is
is assigned to it. I execute the query and then I try to see how many affected rows are returned, if it is more or equal to 1, I throw an alert, else, user is able to register.
Im pretty sure its just some small mistake, but I am kinda new to php so please bear with me. I am aware that my
statement might return false, but why does it complain that I am trying to
on boolean?


Change your select query in:

$stmt2 = $mysqli->prepare("SELECT username FROM Users WHERE username = ?");

And you should use an if statement to have a safe code:

if ($stmt2 = $mysqli->prepare("SELECT username FROM Users WHERE username = ?"))