PYTHON mysql_real_escape_string

is this article helpful?
Python replacement for PHP's mysql_real_escape_string [ edit | history ]
>>> import MySQLdb
>>> db = MySQLdb.connect(host='localhost',user='root',passwd='')
>>> s = "\'sma\\"
>>> db.escape_string(s)

PHP mysql_real_escape_string

PHP original manual for mysql_real_escape_string [ show | ]


(PHP 4 >= 4.3.0, PHP 5)

mysql_real_escape_stringEscapes special characters in a string for use in a SQL statement


string mysql_real_escape_string ( string $unescaped_string [, resource $link_identifier ] )

Escapes special characters in the unescaped_string , taking into account the current character set of the connection so that it is safe to place it in a mysql_query(). If binary data is to be inserted, this function must be used.

mysql_real_escape_string() calls MySQL's library function mysql_real_escape_string, which prepends backslashes to the following characters: \x00, \n, \r, \, ', " and \x1a.

This function must always (with few exceptions) be used to make data safe before sending a query to MySQL.



The string that is to be escaped.


The MySQL connection. If the link identifier is not specified, the last link opened by mysql_connect() is assumed. If no such link is found, it will try to create one as if mysql_connect() was called with no arguments. If by chance no connection is found or established, an E_WARNING level error is generated.

Return Values

Returns the escaped string, or FALSE on error.


Example #1 Simple mysql_real_escape_string() example

// Connect
$link mysql_connect('mysql_host''mysql_user''mysql_password')
    OR die(

// Query
$query sprintf("SELECT * FROM users WHERE user='%s' AND password='%s'",

Example #2 An example SQL Injection Attack

// Query database to check if there are any matching users
$query "SELECT * FROM users WHERE user='{$_POST['username']}' AND password='{$_POST['password']}'";

// We didn't check $_POST['password'], it could be anything the user wanted! For example:
$_POST['username'] = 'aidan';
$_POST['password'] = "' OR ''='";

// This means the query sent to MySQL would be:
echo $query;

The query sent to MySQL:

SELECT * FROM users WHERE user='aidan' AND password='' OR ''=''

This would allow anyone to log in without a valid password.

Example #3 A "Best Practice" query

Using mysql_real_escape_string() around each variable prevents SQL Injection. This example demonstrates the "best practice" method for querying a database, independent of the Magic Quotes setting.


if (isset($_POST['product_name']) && isset($_POST['product_description']) && isset($_POST['user_id'])) {
// Connect

$link mysql_connect('mysql_host''mysql_user''mysql_password');

is_resource($link)) {

"Failed to connect to the server\n";
// ... log the error properly

} else {
// Reverse magic_quotes_gpc/magic_quotes_sybase effects on those vars if ON.

if(get_magic_quotes_gpc()) {
$product_name        stripslashes($_POST['product_name']);
$product_description stripslashes($_POST['product_description']);
        } else {
$product_name        $_POST['product_name'];
$product_description $_POST['product_description'];

// Make a safe query
$query sprintf("INSERT INTO products (`name`, `description`, `user_id`) VALUES ('%s', '%s', %d)",


        if (
mysql_affected_rows($link) > 0) {
"Product inserted\n";
} else {
"Fill the form properly\n";

The query will now execute correctly, and SQL Injection attacks will not work.


Note: A MySQL connection is required before using mysql_real_escape_string() otherwise an error of level E_WARNING is generated, and FALSE is returned. If link_identifier isn't defined, the last MySQL connection is used.

Note: If magic_quotes_gpc is enabled, first apply stripslashes() to the data. Using this function on data which has already been escaped will escape the data twice.

Note: If this function is not used to escape data, the query is vulnerable to SQL Injection Attacks.

Note: mysql_real_escape_string() does not escape % and _. These are wildcards in MySQL if combined with LIKE, GRANT, or REVOKE.

See Also