mysqli::real_escape_string

mysqli::escape_string

mysqli_real_escape_string

(PHP 5, PHP 7)

mysqli::real_escape_string -- mysqli::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 mysqli::escape_string ( string $escapestr ) : string
mysqli::real_escape_string ( string $escapestr ) : string

Procedural style

mysqli_real_escape_string ( mysqli $link , string $escapestr ) : 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 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.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()

escapestr

The string to be escaped.

Characters encoded are NUL (ASCII 0), \n, \r, \, ', ", and Control-Z.

Return Values

Returns an escaped string.

Errors/Exceptions

Executing this function without a valid MySQLi connection passed in will return null and emit E_WARNING level errors.

Examples

Example #1 mysqli::real_escape_string() example

Object oriented style

<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

$mysqli->query("CREATE TEMPORARY TABLE myCity LIKE City");

$city = "'s Hertogenbosch";

/* this query will fail, cause we didn't escape $city */
if (!$mysqli->query("INSERT into myCity (Name) VALUES ('$city')")) {
    printf("Error: %s\n", $mysqli->sqlstate);
}

$city = $mysqli->real_escape_string($city);

/* this query with escaped $city will work */
if ($mysqli->query("INSERT into myCity (Name) VALUES ('$city')")) {
    printf("%d Row inserted.\n", $mysqli->affected_rows);
}

$mysqli->close();
?>

Procedural style

<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

mysqli_query($link, "CREATE TEMPORARY TABLE myCity LIKE City");

$city = "'s Hertogenbosch";

/* this query will fail, cause we didn't escape $city */
if (!mysqli_query($link, "INSERT into myCity (Name) VALUES ('$city')")) {
    printf("Error: %s\n", mysqli_sqlstate($link));
}

$city = mysqli_real_escape_string($link, $city);

/* this query with escaped $city will work */
if (mysqli_query($link, "INSERT into myCity (Name) VALUES ('$city')")) {
    printf("%d Row inserted.\n", mysqli_affected_rows($link));
}

mysqli_close($link);
?>

The above examples will output:

Error: 42000
1 Row inserted.

Notes

Note:

For those accustomed to using mysql_real_escape_string(), note that the arguments of mysqli_real_escape_string() differ from what mysql_real_escape_string() expects. The link identifier comes first in mysqli_real_escape_string(), whereas the string to be escaped comes first in mysql_real_escape_string().

See Also

© 1997–2020 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/mysqli.real-escape-string.php