Why Does `mysqli_real_escape_string()` Throw a 'Parameter Mismatch' Error, and How Can I Fix It?

mysqli_real_Escape_string: Understanding the Parameter Mismatch

When using the mysqli_real_escape_string() function, developers may encounter the error: "mysqli_real_escape_string() expects exactly 2 parameters, 1 given." To resolve this, we need to understand the correct usage of the function and its parameter requirements.

Function Signature

According to the official documentation, the syntax for mysqli_real_escape_string() is:

string mysqli_real_escape_string ( mysqli $link , string $escapestr )

This indicates that the function requires two parameters:

1. $link: A valid MySQLi connection link
2. $escapestr: The string to escape

Common Misconception and Solution

The provided code snippet attempts to check the PHP version to determine whether to use mysqli_real_escape_string() or mysqli_escape_string(). However, it fails because mysqli_real_escape_string() requires a MySQLi connection link as the first parameter, which is missing in the code.

To fix this error, we need to provide the correct parameters to mysqli_real_escape_string(). This can be achieved by establishing a MySQLi connection and passing the connection link as the first argument to the function.

Here's an example of how to use it correctly:

$mysqli = new mysqli('host', 'username', 'password', 'database');

if (phpversion() >= '4.3.0'){
    $string = mysqli_real_escape_string($mysqli, $string);
}else{
    $string = mysqli_escape_string($mysqli, $string);
}

In this code, the $mysqli variable represents a valid MySQLi connection link, which is passed to mysqli_real_escape_string() along with the $string to be escaped. This should resolve the error and allow you to use mysqli_real_escape_string() as intended.

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