mysqli::real_connect
Note that this function will NOT escape _ (underscore) and % (percent) signs, which have special meanings in LIKE clauses.
As far as I know there is no function to do this, so you have to escape them yourself by adding a backslash in front of them.
mysqli::real_escape_string
mysqli_real_escape_string
(PHP 5)
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
Oriented object style
string mysqli::real_escape_string
( string $escapestr
)
Procedural style
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.
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.
Examples
Example #1 mysqli::real_escape_string() example
Oriented object 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.
See Also
- mysqli_character_set_name() - Returns the default character set for the database connection
add a note
User Contributed Notes
mysqli::real_escape_string - [5 notes]
arnoud at procurios dot nl ¶
8 years ago
Josef Toman ¶
3 years ago
For percent sign and underscore I use this:
<?php
$more_escaped = addcslashes($escaped, '%_');
?>
tobias_demuth at web dot de ¶
7 years ago
Note, that if no connection is open, mysqli_real_escape_string() will return an empty string!
dave at mausner.us ¶
2 years ago
You can avoid all character escaping issues (on the PHP side) if you use prepare() and bind_param(), as an alternative to placing arbitrary string values in SQL statements. This works because bound parameter values are NOT passed via the SQL statement syntax.
vita dot plachy at seznam dot cz ¶
5 years ago
The above can be managed by the following function:
<?php
function search_escape($str, $char = '\\')
{
return ereg_replace('[%_]', $char . '\0', $str);
}
?>