Add the following lines to your mysql.lsp library, depending on the version of mysql client lib you have:
(import libmysqlclient "mysql_escape_string") ; MySQL4
(import libmysqlclient "mysql_real_escape_string") ; MySQL5
MySQL4
(define (escape value , safe-value)
"Escapes input value using mysql_escape_string."
(set 'safe-value (dup " " (+ 1 (length value))))
(MySQL:mysql_escape_string safe-value value (length value))
safe-value)
MySQL5
(define (escape value , safe-value)
"Escapes input value using mysql_real_escape_string."
(set 'safe-value (dup " " (+ 1 (length value))))
(MySQL:mysql_real_escape_string MySQL:MYSQL safe-value value (length value))
safe-value)
These will escape newlines, single and double ticks, etc, to prevent sql injection.