Search for REPLACE in the Links SQL forum - been discussed tons of times.
http://gossamer-threads.com/perl/gforum/gforum.cgi?do=search_results&search_forum=cat_5&search_string=REPLACE&search_type=AND&search_fields=sb&search_time=&search_user_username=&mh=50
http://gossamer-threads.com/perl/gforum/gforum.cgi?do=search_results&search_forum=cat_5&search_string=REPLACE&search_type=AND&search_fields=sb&search_time=&search_user_username=&mh=50