Add
or die(mysql_error());
into your code in order to get full explanation regarding the error you are getting from mysql
so replace your query with the following code
$chr1 = mysql_query("SELECT olympiad_nobles.char_name,olympiad_nobles.olympiad_points,olympiad_nobles.competitions_done,olympiad_nobles.class_id,class_list.class_name,class_list.id
FROM class_list,olympiad_nobles
WHERE ((olympiad_nobles.competitions_done >=1) AND (class_list.id=88) AND (olympiad_nobles.class_id=88))
ORDER BY olympiad_nobles.olympiad_points DESC") or die(mysql_error());