mysqli::real_escape_string

mysqli_real_escape_string

(PHP 5, PHP 7, PHP 8)

mysqli::real_escape_string -- mysqli_real_escape_string — Escapes special characters in a string for use in an SQL statement, taking into account the current charset of the connection

Description

Object-oriented style

public function mysqli::real_escape_string(string $string): string

Procedural style

function mysqli_real_escape_string(mysqli $mysql, string $string): string

This function is used to create a legal SQL string that you can use in an SQL statement. The given string is encoded to produce an escaped SQL string, taking into account the current character set of the connection.

Caution

Security: the default character set

The character set must be set either at the server level, or with the API function mysqli_set_charset() for it to affect mysqli_real_escape_string(). See the concepts section on character sets for more information.

Warning

This function does not add quotes around the result; they must be added by the caller. If the NO_BACKSLASH_ESCAPES SQL mode is enabled on the connection, only the single quote (') is escaped, so a value placed between double quotes (") can terminate the string and allow SQL injection. Use prepared statements instead. If that is not possible, use mysqli::quote_string(), which always wraps the result in single quotes.

Parameters

mysql

Procedural style only: A mysqli object returned by mysqli_connect() or mysqli_init()

string

The string to be escaped.

Characters encoded are NUL (ASCII 0), \n, \r, \, ', ", and CTRL+Z. If the NO_BACKSLASH_ESCAPES SQL mode is enabled on the connection, only ' is encoded, by doubling it.

Return Values

Returns an escaped string.

Examples

Example #1 mysqli::real_escape_string() example

Object-oriented style

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

$city = "'s-Hertogenbosch";

/* this query with escaped $city will work */
$query = sprintf("SELECT CountryCode FROM City WHERE name='%s'",
    $mysqli->real_escape_string($city));
$result = $mysqli->query($query);
printf("Select returned %d rows.\n", $result->num_rows);

/* this query will fail, because we didn't escape $city */
$query = sprintf("SELECT CountryCode FROM City WHERE name='%s'", $city);
$result = $mysqli->query($query);

Procedural style

<?php

mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = mysqli_connect("localhost", "my_user", "my_password", "world");

$city = "'s-Hertogenbosch";

/* this query with escaped $city will work */
$query = sprintf("SELECT CountryCode FROM City WHERE name='%s'",
    mysqli_real_escape_string($mysqli, $city));
$result = mysqli_query($mysqli, $query);
printf("Select returned %d rows.\n", mysqli_num_rows($result));

/* this query will fail, because we didn't escape $city */
$query = sprintf("SELECT CountryCode FROM City WHERE name='%s'", $city);
$result = mysqli_query($mysqli, $query);

The above examples will output something similar to:

Select returned 1 rows.

Fatal error: Uncaught mysqli_sql_exception: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 's-Hertogenbosch'' at line 1 in...

See Also