MySql Insert into.....(error) - php

Question

I'm getting an insert error when I'm trying to insert data from a form to my database. the error is as follows :
Error: INSERT INTO users (firstname) VALUES ('a')
This is the code:
if ( isset($_POST['submit']) ) {
$registerfirstname = $_POST['firstname'];
$query = "INSERT INTO users (firstname) VALUES ('$registerfirstname')";
if(mysqli_query($conn, $query)){
echo "New user created";
}else{
echo "Error: " .$query. "<br>" . mysqli_error($conn);
}
}

Answer 1

You are making a little mistake here. You have to pass the variable data through the mysqli_real_escape_string() through first. An example would be ,
$registerfirstname = mysqli_real_escape_string($registerfirstname);
And after that you can use it in sql like that. This way it is more sanitized. I hope this will solve your problem.

Answer 2

Firstly, you should use Mysql Workbenck to prepare sql statements. If, The statements properly work on workbench.Paste into the php script.
On php side, you should use mysql_real_escape_string() function before set your variable.
Like;
$registerfirstname = mysql_real_escape_string($_POST['firstname']);

Answer 3

Try this:
// Create connection
$connection = new mysqli('localhost', 'username', 'password', 'dbname');
// Check connection
if ($connection->connect_error) {
die("Connection failed: " . $connection->connect_error);
}
$firstname = "John";
$firstname = mysqli_real_escape_string($firstname);
$sql = "INSERT INTO users (firstname) VALUES ('$firstname')";
if ($connection->query($sql) === TRUE) {
echo "New user created";
} else {
echo "Error: " . $sql . "<br>" . $connection->error;
}
// Close connection
$connection->close();
It should work, but if it doesn't just give us what errors are shown.