requete top mineur tout minerai confondu :
SELECT player,COUNT(*) AS total FROM block GROUP BY player ORDER BY total DESC

requete top mineur d'un block en particulier :
SELECT player,COUNT(*) AS total FROM block WHERE id='15' GROUP BY player ORDER BY total DESC

insert into block (player, id)
select 'meka','15'
union
select 'blou','18'
union
select 'blou','15'
union
select 'blou','16'
union
select 'blou','15'
union
select 'meka','15'
union
select 'meka','16'

Pour faire des requetes tout ça :
http://forums.bukkit.org/threads/lib-tut-mysql-sqlite-bukkit-drivers.33849/
http://java.developpez.com/faq/jdbc/?page=resultset#valeursRS
http://java.developpez.com/faq/jdbc/?page=metadataresultset