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mysqli::quote_string

PHP function Edit on GitHub ✎

(PHP 8 >= 8.6.0)

Quotes and escapes a string for use in an SQL statement

Description

Oop

mysqli::quote_string(string $string): string

Procedural

mysqli_quote_string(mysqli $mysql, string $string): string

Creates a legal SQL string literal that can be used in an SQL statement. The given string is escaped in the same way as mysqli::real_escape_string, taking into account the current character set of the connection, and the result is wrapped in single quotes. The returned value must therefore be inserted into the query without adding any further quotes around it.

Unlike mysqli::real_escape_string, the result is also safe when the NO_BACKSLASH_ESCAPES SQL mode is enabled on the connection.

Caution

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

Note

Quoting is only suitable for string literals. It does not make identifiers, such as table or column names, safe. Whenever possible, use prepared statements instead of building queries manually.

Parameters

string

The string to be quoted and escaped.

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

Return Values

Returns the escaped string enclosed in single quotes.

Examples

mysqli::quote_string example

Oop

php
<?php

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

$city = "'s-Hertogenbosch";

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

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

Procedural

php
<?php

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

$city = "'s-Hertogenbosch";

/* this query with quoted $city will work */
$query = sprintf("SELECT CountryCode FROM City WHERE name=%s", mysqli_quote_string($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 quote and escape $city */
$query = sprintf("SELECT CountryCode FROM City WHERE name='%s'", $city);
$result = mysqli_query($mysqli, $query);

Similar

output
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

  • mysqli::real_escape_string
  • mysqli::set_charset

Source: reference/mysqli/mysqli/quote-string.xml · from the official PHP manual (php/doc-en)