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我有一个足球台球网站。每周，我的朋友都会挑选每场比赛的获胜者。我想将每个球员的选秀权与其他球员进行比较，并列出相似的百分比。我发现这个页面可以帮助我计算特定一周的相似度：比较标签组以查找 PHP/MySQL 的相似度/分数。感谢 Ivar Bonsaksen，他的解决方案效果很好！

我现在要做的是显示过去几周每个玩家的累积相似度。

我有 3 个表要查询：配置文件 (spprofiles)、游戏 (sp6games) 和精选 (sp6picks)。另一个名为 Teams (sp6teams) 的表用于获取团队的名称，但在这里无关紧要。

Profiles (spprofiles)
+-----------+-------------+
| profileID | profilename |
+-----------+-------------+
| 52        | My Team A   |
| 53        | Some Team B |
+-----------+-------------+

Games (sp6games)
+--------+--------+---------+------+
| gameID | weekID | visitor | home |
+--------+--------+---------+------+
| 1      | 2      | 9       | 21   |
| 2      | 2      | 14      | 6    |
| 17     | 3      | 6       | 9    |
| 18     | 3      | 30      | 21   |
+--------+--------+---------+------+

Picks (sp6picks)
+-----------+--------+------+
| profileID | gameID | pick |
+-----------+--------+------+
| 52        | 1      | 21   |
| 52        | 2      | 6    |
| 52        | 17     | 12   |
| 52        | 18     | 21   |
| 53        | 1      | 9    |
| 53        | 2      | 6    |
| 53        | 17     | 9    |
| 53        | 18     | 21   |
+-----------+--------+------+

本周的查询如下所示：

$weekID = 3; //the current weekID
$profile = 52; //the current ProfileID

SELECT
  targetProfiles.profileID AS targetID,
  sourceProfiles.profileID AS sourceID,
    COUNT(targetProfiles.profileID)
    /
    (((SELECT COUNT(*) FROM sp6Picks LEFT JOIN sp6Games USING (gameID) WHERE profileID = sourceProfiles.profileID AND weekID = $weekID)
      +
    (SELECT COUNT(*) FROM sp6Picks LEFT JOIN sp6Games USING (gameID) WHERE profileID = targetProfiles.profileID AND weekID = $weekID))/2)
  AS similarity
FROM
  spProfiles AS sourceProfiles
  LEFT JOIN
    (SELECT sp6Picks.* FROM sp6Picks LEFT JOIN sp6Games USING (gameID) WHERE weekID = $weekID) AS sourcePicks
    ON (sourcePicks.profileID = sourceProfiles.profileID)
  INNER JOIN
    (SELECT sp6Picks.* FROM sp6Picks LEFT JOIN sp6Games USING (gameID) WHERE weekID = $weekID) AS targetPicks
    ON (sourcePicks.pick = targetPicks.pick AND sourcePicks.profileID != targetPicks.profileID)
  LEFT JOIN
    spProfiles AS targetProfiles
    ON (targetPicks.profileID = targetProfiles.profileID)
WHERE sourceProfiles.profileID = $profile
GROUP BY targetID

如果我分别在几周内运行此查询，我会得到以下结果：

$weekID = 2;
+----------+----------+------------+
| targetID | sourceID | similarity |
+----------+----------+------------+
| 53       | 52       | 0.5000     |
+----------+----------+------------+

$weekID = 3;
+----------+----------+------------+
| targetID | sourceID | similarity |
+----------+----------+------------+
| 53       | 52       | 0.5000     |
+----------+----------+------------+

到目前为止，我为累积计算出的查询看起来像这样（但我尝试了其他几种变体）。基本上，我只是将 WHERE 子句更改为包括前几周weekID <= $weekID，并将 Games 表添加到主 FROM 子句LEFT JOIN sp6games ON (targetPicks.gameID = sp6games.gameID)中。

$weekID = 3; //the current weekID
$profile = 52; //the current ProfileID

SELECT
  targetProfiles.profileID AS targetID,
  sourceProfiles.profileID AS sourceID,
    COUNT(targetProfiles.profileID)
    /
    (((SELECT COUNT(*) FROM sp6Picks LEFT JOIN sp6Games USING (gameID) WHERE profileID = sourceProfiles.profileID AND weekID <= $weekID)
      +
    (SELECT COUNT(*) FROM sp6Picks LEFT JOIN sp6Games USING (gameID) WHERE profileID = targetProfiles.profileID AND weekID <= $weekID))/2)
  AS similarity
FROM
  spProfiles AS sourceProfiles
  LEFT JOIN
    (SELECT sp6Picks.* FROM sp6Picks LEFT JOIN sp6Games USING (gameID) WHERE weekID <= $weekID) AS sourcePicks
    ON (sourcePicks.profileID = sourceProfiles.profileID)
  INNER JOIN
    (SELECT sp6Picks.* FROM sp6Picks LEFT JOIN sp6Games USING (gameID) WHERE weekID <= $weekID) AS targetPicks
    ON (sourcePicks.pick = targetPicks.pick AND sourcePicks.profileID != targetPicks.profileID)
  LEFT JOIN
    spProfiles AS targetProfiles
    ON (targetPicks.profileID = targetProfiles.profileID)
  LEFT JOIN sp6games ON (targetPicks.gameID = sp6games.gameID)
WHERE sourceProfiles.profileID = $profile
GROUP BY targetID, weekID

合并后的结果应该是 0.5000，但我得到的是：

$weekID = 3;
+----------+----------+------------+
| targetID | sourceID | similarity |
+----------+----------+------------+
| 53       | 52       | 0.7500     |
+----------+----------+------------+

问题是COUNT(targetProfiles.profileID)在几周内没有正确总计，因此similarity值被搞砸了。对于更大的数据集，它似乎也不是很有效。

感谢您花时间阅读，并可能提供帮助。

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1 回答 1

2 
SELECT   t.profileID                 AS target,
         SUM(s.pick=t.pick)/COUNT(*) AS similarity
FROM     sp6picks s
    JOIN sp6picks t USING (gameID)
    JOIN sp6games g USING (gameID)
WHERE    g.weekID    <= 3
     AND s.profileID != t.profileID
     AND s.profileID  = 52
GROUP BY t.profileID

在sqlfiddle上查看。

于 2012-10-21T05:47:56.743 回答