Several functions for anti-SQL injection

Do not trust the user's input in the login, you need to process the user's input

SQL injection:

' or 1=1 #

Several functions to prevent SQL injection:

Addslashes ($string): Use a backslash to refer to a special character in a string ' "\

$username =addslashes ($username);

Mysql_escape_string ($string): Use backslashes to escape special characters in a string for mysql_query () queries.

$username =mysql_escape_string ($username);

Mysql_real_escape_string ($string): Escapes special characters in the string used in the SQL statement and takes into account the current character set of the connection to ensure that the function is currently connected, otherwise a warning is reported. Do not escape% with _

$username =mysql_real_escape_string ($username);

Several functions for anti-SQL injection