Code:
if (isset($_POST['criar'])) {
$nome = $_POST['nome'];
$apelido = $_POST['apelido'];
$email = $_POST['email'];
$pass = $_POST['pass'];
$data = date("Y/m/d");
$email_check = mysqli_query("SELECT email FROM users WHERE email='$email'");
$do_email_check = mysqli_num_rows($email_check);
if ($do_email_check >= 1) {
echo '<h3>Este email já está registado, faça o login, caso seja o seu, entre <a href="login.php">aqui!</a></h3>';
}elseif ($nome == '' OR strlen($nome)<3) {
echo '<h3>Escreva seu nome corretamente!</h3>';
}elseif ($email == '' OR strlen($email)<10) {
echo '<h3>Escreva seu email corretamente!</h3>';
}elseif ($pass == '' OR strlen($pass)<8) {
echo '<h3>Escreva a palavra-passe corretamente, deve possuir no mínino 8 caracteres!</h3>';
}else{
$query = "INSERT INTO users (`nome`,`apelido`,`email`,`password`,`data`) VALUES ('$nome','$apelido','$email','$pass','$data')";
$data = mysqli_query($query) or die(mysqli_error());
if ($data) {
setcookie("login",$email);
header("Location: ./");
}else{
echo "<h3>Desculpe, houve um erro ao registar-se...</h3>";
}
}
}
The errors are self-explanatory, mysqli_query requires 2 parameters - the documentation is available here: https://php.net/mysqli_query
As per the docs, the first parameter is your database connection created through mysqli_connect.
Your could should read similar to:
$db = mysqli_connect(..);
// ..
$email_check = mysqli_query($db, "SELECT email FROM users WHERE email='$email'");
Also, your code is vulnerable to SQL injection, you should consider using parameters in your query with code such as:
if ($stmt = mysqli_prepare($db, "SELECT email FROM users WHERE email = ?"))
{
mysqli_stmt_bind_param($stmt, "s", $email);
mysqli_stmt_execute($stmt);
$email_check = mysqli_stmt_num_rows($stmt);
}
TL;DR You need to supply the connection to query in the mysqli_query function.
I suppose you are asking why you are getting these error messages. The first message specifiec that you need to have two parameters in the mysqli_query call. The first is the connection to your server, the second is the query itself.
Here is an example from https://www.w3schools.com/php/func_mysqli_query.asp
<?php
$con=mysqli_connect("localhost","my_user","my_password","my_db");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
// Perform queries
mysqli_query($con,"SELECT * FROM Persons");
mysqli_query($con,"INSERT INTO Persons (FirstName,LastName,Age)
VALUES ('Glenn','Quagmire',33)");
mysqli_close($con);
?>
The second error message is because the $email_check will become null when the msqli_query call fails, therefore making msqli_num_rows fail. Note that you will obviously have to change all myqsli_query calls. Here is a link to the manual if you want to read more about the call, http://php.net/manual/en/mysqli.query.php.