/*Format : LIMIT a - 1, b - (a - 1)
ROUND(lat/lon, n)
ORDER BY city DESC(ra) OR ASC(al)
*/
SELECT ROUND(MAX(SQRT(POW(x1 - x2, 2) + POW(y1 - y2, 2))), 4),
ROUND(MIN(SQRT(POW(x1 - x2, 2) + POW(y1 - y2, 2))), 4)
FROM ((SELECT id, ROUND(lat, 3) x1, ROUND(lon, 3) y1
FROM citytable GROUP BY x1, y1 ORDER BY city DESC, id LIMIT 5, 9) AS tt1
JOIN
(SELECT id, ROUND(lat, 3) x2, ROUND(lon, 3) y2
FROM citytable GROUP BY x2, y2 ORDER BY city DESC, id LIMIT 5, 9) AS tt2
ON tt1.id<>tt2.id AND tt1.id<tt2.id);