The php Function Mysql_Real_Escape_String

The php function mysql_real_escape_string escapes the given string to make it legal to use in an SQL statement, taking into account the current character set of the MySQL connection. This escaping makes the query safe against SQL injection attacks.

The mysql_real_escape_string function must be used to make sure all strings that will be passed into MySQL are escaped properly. This is a crucial security measure that helps prevent SQL injection attacks, which can give attackers access to private data or execute queries that they were not authorized to do.

For example, if you have a string that contains a backslash or an apostrophe, it will be interpreted as part of the string and interfere with normal MySQL functioning. You need to escape these characters using mysql_real_escape_string before you can use it in a query.

Mysql_real_escape_string also handles multi-byte characters differently than the addslashes() function, which can be tricked into adding a backslash for a single quote ('') in certain multi-byte character sets, such as UTF-8.

While mysql_real_escape_string is a valuable tool, it is not necessary if you use the newer prepared statements in your database queries. Prepared statements are much more secure and require less code than using mysql_real_escape_string. For more information on utilizing prepared statements, see the article: How do I create and use a prepared statement in php?. Also, you should be familiar with and integrating the native database abstraction library PDO rather than mysql_real_escape_string. PDO handles all of the database sanitization for you, making your code cleaner and safer.