順位を取得。※但し参照するレコードが増えるとクソ重い

pointフィールドを元に、降順で自分の順位を求める。※存在しないidでも_rank_が1になるので要注意

▼pointが同値の場合、タイ扱い

SELECT count(*)+1 AS _rank_
FROM HOGE_TABLE
WHERE point > (select point FROM HOGE_TABLE WHERE id = ?);

▼pointが同値の場合、DISTINCTでまとめて重複を除外

SELECT count(DISTINCT point)+1 AS _rank_
FROM  HOGE_TABLE
WHERE point > (select point FROM HOGE_TABLE WHERE id = ?)

指定順位（5〜10位）のランキングを降順で取得

実装する場合は順位をプレースホルダにすればいいよ。
▼pointが同値の場合、タイ扱い

SELECT
    tmpTable1.id,
    tmpTable1.point,
    (
        SELECT count(tmpTable2.point)
        FROM HOGE_TABLE as tmpTable2
        WHERE tmpTable2.point > tmpTable1.point
    )+1 as _rank_
FROM  HOGE_TABLE as tmpTable1
WHERE ( SELECT count(tmpTable2.point) FROM HOGE_TABLE as tmpTable2 WHERE tmpTable2.point > tmpTable1.point )+1 >= 5
AND   ( SELECT count(tmpTable2.point) FROM HOGE_TABLE as tmpTable2 WHERE tmpTable2.point > tmpTable1.point )+1 <= 10
ORDER BY tmpTable1.point DESC

▼pointが同値の場合、DISTINCTでまとめて重複を除外

SELECT
    DISTINCT
        tmpTable1.point,
        (
            SELECT count(DISTINCT tmpTable2.point)
            FROM HOGE_TABLE as tmpTable2
            WHERE tmpTable2.point >= tmpTable1.point
        ) as _rank_
FROM  HOGE_TABLE as tmpTable1
WHERE ( SELECT count(DISTINCT tmpTable2.point) FROM HOGE_TABLE as tmpTable2 WHERE tmpTable2.point > tmpTable1.point )+1 >= 5
AND   ( SELECT count(DISTINCT tmpTable2.point) FROM HOGE_TABLE as tmpTable2 WHERE tmpTable2.point > tmpTable1.point )+1 <= 10
ORDER BY tmpTable1.point DESC