Question

我的数据库中只有以下表格：

得分表

字段............... | ........类型......... | ..Null .. | ..Key .. | ...........默认................. | ..Extra
  .................................................. .................................................. ...........................................
  ID .................... | ........... INT（20）... | ..NO ... | .. PRI .. | ..NULL ............................. | ..auto_increment
  SCR .................. | ........... INT（20）... | ..NO ... | .... ...... | ..... 0 ................................. | ... .......................
  PLAYER_NAME .. | ..varchar（150）.. | ..NO ... | .......... | ..NULL ................ ............ | .........................
位置....... .... | .varchar（5）....... | ..NO ... | .......... | ..NULL ........... ................. | .........................
  DateUpdated .. | ..timestamp ...... | ..NO ... | .......... | CURRENT_TIMESTAMP | ..on更新

目前我在id字段上有一个索引。

我在处理100万条记录。每个玩家只有一个记录在数据库中。

我想根据以下示例检索名为：john的特定玩家的全球排名，其中id为：682：

秩..........标识....... SCR ...... DateUpdated
  -------------------------------------------------- -----------
  15257 ... 53264 ....... 62 ........ 2013-3-10 16:45:37
  15258 ... 3533 ......... 62 ........ 2013-3-10 16:45:37
  15259 ... 7283 ......... 62 ........ 2013-3-13 16:45:37
  15260 ... 386 ........... 61 ........ 2013-3-09 18:55:25
  15261 ... 78252 ....... 61 ........ 2013-3-10 13:33:21
  15262 ... 682 ........... 61 ........ 2013-3-10 16:45:37＆lt; ==这是我们的播放器
  15263 ... 9263 ......... 61 ........ 2013-3-10 16:45:37
  15264 ... 7263 ......... 61 ........ 2013-3-10 16:56:25
  15265 ... 7826 ......... 60 ........ 2013-3-10 12:26:37
  15266 ... 9276 ......... 60 ........ 2013-3-10 15:22:37
  15267 ... 932872 ..... 60 ........ 2013-3-13 11:45:37

玩家出现在中间，上方有5名玩家，下方有5名玩家请注意，排名按scr排序，然后是DateUpdated

这是我的查询，它带来了这些结果：

 SELECT id,
  scr,
  player_name,
  location,
  dateupdated,
  rank
FROM
  (SELECT id,
    scr,
    player_name,
    location,
    dateupdated
  FROM scores
  WHERE id IN
    (SELECT id
    FROM
      (SELECT id
      FROM scores
      WHERE id IN
        (SELECT id
        FROM scores
        WHERE scr >=
          (SELECT scr FROM scores WHERE id = 1140188
          )
        AND id     != 1140188
        AND id NOT IN
          (SELECT id
          FROM scores
          WHERE scr IN
            (SELECT scr FROM scores WHERE id = 1140188
            )
          AND dateupdated >=
            (SELECT dateupdated FROM scores WHERE id = 1140188
            )
          )
        ORDER BY scr ASC,
          dateupdated ASC
        )
      ORDER BY scr,
        dateupdated ASC limit 0,
        5
      ) AS t
    UNION ALL
    SELECT id FROM
      (SELECT id FROM scores WHERE id = 1140188
      ) AS g
    UNION ALL
    SELECT id
    FROM
      (SELECT id
      FROM scores
      WHERE id IN
        (SELECT id
        FROM scores
        WHERE scr <=
          (SELECT scr FROM scores WHERE id = 1140188
          )
        AND id     != 1140188
        AND id NOT IN
          (SELECT id
          FROM scores
          WHERE scr IN
            (SELECT scr FROM scores WHERE id = 1140188
            )
          AND dateupdated <
            (SELECT dateupdated FROM scores WHERE id = 1140188
            )
          )
        ORDER BY scr ASC,
          dateupdated ASC
        )
      ORDER BY scr DESC,
        dateupdated ASC limit 0,
        5
      ) AS s
    )
  ORDER BY scr DESC,
    dateupdated ASC
  ) AS A
LEFT JOIN
  (SELECT l.id             AS id2,
    @curRow := @curRow + 1 AS Rank
  FROM scores l
  JOIN
    (SELECT @curRow := 0
    ) r
  ORDER BY scr DESC,
    dateupdated ASC
  ) AS B ON A.id = B.id2;

但是这个查询在我的本地计算机上大约需要8秒，并且它消耗了大量资源，在Web服务上实现这一点将最终导致灾难。

任何人都可以提供任何提示，即使是一个全新的查询也欢迎..

请帮助!!!!!

Answer 1

SELECT
all_ranked.*
FROM (select rank 
      from (SELECT l.id             AS id2,
            @curRow := @curRow + 1 AS Rank
            FROM scores l
            JOIN
                (SELECT @curRow := 0) r
                ORDER BY scr DESC, dateupdated ASC
            ) AS B) 
      where B.id=1234567) as rank_record, <--- just one record - value of rank
      (SELECT l.id             AS id2,
            @curRow := @curRow + 1 AS Rank
            FROM scores l
            JOIN
                (SELECT @curRow := 0) r
                ORDER BY scr DESC, dateupdated ASC
            ) AS all_ranked <--- all ranked users
where all_ranked.rank>=rank_record.rank-5 and all_ranked.rank>=rank_record.rank+5;

MySql：获得排名繁重的查询优化 - 需要帮助

1 个答案: