查询 parents 和 hierarchyID table 的前两个 children

Question

我正在尝试从使用 HiearchyID 的单个 table 中获取 Parent 及其左上角和右上角 children。几个星期以来我一直在努力解决这个问题，希望得到任何帮助。

这是一个为学校辩论队存储 'facts' 的单个 table，每个事实都有 child 个可以是 'for' 或 'against' 的事实parent 事实。我想获取摘要页面的 parent 和最近的 'for' 以及最近的 'against' 事实。相反，我得到的是 cross-union 每个组合。

这是我的 table:

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.

备注：

TOP(1) 会起作用，但我的真实 table 有许多顶级 parent。
根事实总是第 2 级，最上面的两个树级基本上只是占位符。
我在 SQL Server 2014 上使用 T-SQL。

非常感谢任何提示或解决方案！

Answer 1

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。

查询 parents 和 hierarchyID table 的前两个 children

Query for parents and top two children of a hierarchyID table

sql

select

hierarchyid