Question

I want to eliminate sql injection, should I use mysqli_real_escape_string() or is it clear in mysqli?
For example

$nick = mysqli_real_escape_string($_POST['nick'])

Answer 1

You should use prepared statements and pass string data as a parameter but you should not escape it.

This example is taken from the documentation:

/* create a prepared statement */
if ($stmt = $mysqli->prepare("SELECT District FROM City WHERE Name=?")) {

    /* bind parameters for markers */
    $stmt->bind_param("s", $city);

    /* execute query */
    $stmt->execute();

    /* bind result variables */
    $stmt->bind_result($district);

    /* fetch value */
    $stmt->fetch();

    printf("%s is in district %s\n", $city, $district);

    /* close statement */
    $stmt->close();
}

Note that the example does not call mysqli_real_escape_string. You would only need to use mysqli_real_escape_string if you were embedding the string directly in the query, but I would advise you to never do this. Always use parameters whenever possible.

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