Sorry for triple post but... I've no idea why it doesn't insert the "\". Tried with:
local name = string.gsub(getPlayerName(name), "s/\|", "s/\\|")
query = mysql_query(connect_mysql, "INSERT INTO `"..mapname.."` (name, time, date, serial, tag) VALUES('"..name.."', '"..time.."', '"..date.."', '"..serial.."','".. tag.."')")