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我正在尝试从使用 HiearchyID 的单个表中获取父级及其左上角和右上角的子级。几周来一直在努力，希望能得到任何帮助。

这是一个为学校辩论队存储“事实”的表，每个事实都有子事实，可以“支持”或“反对”父事实。我想获取摘要页面的父项以及最近的“支持”和最近的“反对”事实。相反，我得到了一个与这些组合的交叉联合。

这是我的桌子：

factID (key)    nodeID (hierarchyID)    nodeLevel(computed column) text                        side(1=for, 2=against)  timestamp
=======         ======                   =========                 ====                        =====                     =========
1              /1/2/                     2                         "Kirk rules"                1                         08:00
3              /1/2/1/                   3                         "Great actor!"              1                         08:01
5              /1/2/2/                   3                         "Picard is better."         2                         08:02
7              /1/2/3/                   3                         "best captain ever"         1                         08:03
32             /1/2/4/                   3                         "hate his over-acting"      2                         08:04
43             /1/2/5/                   3                         "PriceLine is great."       1                         08:05
44             /1/2/6/                   3                         "Spock was better too."     2                         08:06

这是我当前的查询：

SELECT P.text AS parentText, P.timeStamp AS parentTimeStamp,  
           L.text AS leftText,  MAX(L.timeStamp) AS leftTimeStamp, 
           R.text AS rightText, MAX(R.timeStamp) AS rightTimeStamp   

FROM app.Facts AS P 
    LEFT OUTER JOIN app.Facts AS L 
            ON (P.nodeID = (L.nodeID).GetAncestor(1))  AND (L.sideID = 1 OR L.sideID IS NULL)

    LEFT OUTER JOIN app.Facts AS R
        ON (P.nodeID = (R.nodeID).GetAncestor(1))  AND (R.sideID = 2 OR R.sideID IS NULL)

WHERE (P.text IS NOT NULL) AND (P.nodeLevel = 2)     

GROUP BY P.text, P.timeStamp, L.text, L.timeStamp, R.text, R.timeStamp
HAVING L.timeStamp = MAX(L.timeStamp) AND R.timeStamp = MAX(R.timeStamp)
ORDER BY P.timeStamp DESC, L.timeStamp DESC, R.timeStamp DESC

这是我想要得到的：

parentText      parentTimeStamp leftText                 leftTimeStamp  rightText              rightTimeStamp
==========      =============== =====================   =============   =========               ==============
"Kirk rules"    08:00           "PriceLine is great."   08:05          "Spock was better too."  08:06
...
"top fact xx"   11:00           'for' fact xx           11:01          'against' fact xx        11:01

这是我得到的：

parentText  parentTimeStamp leftText                leftTimeStamp   rightText                rightTimeStamp
==========  =============== =====================   =============   =========                ==============
"Kirk rules"    08:00       "PriceLine is great."   08:05           "Spock was better too."   08:06
"Kirk rules"    08:00       "PriceLine is great."   08:05           "hate his over-acting"    08:04
"Kirk rules"    08:00       "PriceLine is great."   08:05           "Picard is better."       08:02
"Kirk rules"    08:00       "best captain ever"     08:03           "Spock was better too."   08:06
"Kirk rules"    08:00       "best captain ever"     08:03           "hate his over-acting"    08:04
"Kirk rules"    08:00       "best captain ever"     08:03           "Picard is better."       08:02
"Kirk rules"    08:00       "Great actor!"          08:01           "Spock was better too."   08:06
"Kirk rules"    08:00       "Great actor!"          08:01           "hate his over-acting"    08:04
"Kirk rules"    08:00       "Great actor!"          08:01           "Picard is better."       08:02
...
same thing with rest of the top level facts.

笔记：

  1. 如果只有一个父级，TOP(1) 将起作用，但我的真实表有许多顶级父级。
  2. 根事实总是第 2 级，顶部的两个树级别基本上只是占位符。
  3. 我在 SQL Server 2014 上使用 T-SQL。

非常感谢任何提示或解决方案！

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1 回答 1

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我通过添加两列找到了解决方法：

isLatestForArg     BIT  NOT NULL,
isLatestAgainstArg BIT  NOT NULL

然后将我的查询更改为：

SELECT P.text AS parentText, P.timeStamp AS parentTimeStamp,  
       L.text AS leftText,  MAX(L.timeStamp) AS leftTimeStamp, 
       R.text AS rightText, MAX(R.timeStamp) AS rightTimeStamp   

FROM app.Facts AS P 
LEFT OUTER JOIN app.Facts AS L 
        ON (P.nodeID = (L.nodeID).GetAncestor(1))  AND ((L.sideID IS NULL) OR (L.isLatestForArg = 1))

LEFT OUTER JOIN app.Facts AS R
    ON (P.nodeID = (R.nodeID).GetAncestor(1))  AND ((R.sideID IS NULL) OR (R.isLatestAgainstArg = 1))

显然不理想，因为现在每个 INSERT 都需要更新 isLatestFor/Against 标志。

于 2015-07-17T13:29:17.743 回答