在SQL查询中输出交叉引用矩阵结果

假设我有一个包含4条Id为1到4的记录的主表

然后，我有一个事务表，它维护一个记录到另一个记录的兼容性

Record1    Record2    IsCompatible
1          2          True
1          3          True
4          1          False
2          3          False
4          2          True
3          4          True

只有一条记录具有相同的Record1/Record2组合，但在这些记录中，确定给定记录是作为Record1还是Record2保存的逻辑取决于设置兼容性时源记录是什么。因此，任何记录在任何时候都可能是双向的

从这里，我想输出一个类似以下内容的记录集：

RecordID    CompatabilityString
1           Null, True, True, False
2           True, Null, False, True
3           True, False, Null, True
4           False, True, True, Null

CompatibilityString以数字顺序返回每个项与所有其他项的兼容性，null表示与自身的关系

实现这一目标的最佳方式是什么

---

干杯

首先，您应该将此表与其自身合并，以获得完整的矩阵，然后使用

MAX（CASE…）

旋转此表：

如果

兼容性字符串只需要一列

：

SELECT X as RecordID,
       ISNULL(MAX(CASE WHEN Y=1 THEN IsCompatible END),'NULL')+
       ','+       
       ISNULL(MAX(CASE WHEN Y=2 THEN IsCompatible END),'NULL')+
       ','+       
       ISNULL(MAX(CASE WHEN Y=3 THEN IsCompatible END),'NULL')+
       ','+       
       ISNULL(MAX(CASE WHEN Y=4 THEN IsCompatible END),'NULL')
       as CompatabilityString 


FROM
(
    SELECT Record1 as X,Record2 as Y,IsCompatible FROM T
    UNION ALL
    SELECT Record2 as X,Record1 as Y,IsCompatible FROM T
) as T1
GROUP BY X
ORDER BY X

UPD:这里是关于可变维度的第二个查询。在本例中，XML路径的

用于创建逗号分隔的列表：

;WITH T1 AS
(
    SELECT Record1 as X,Record2 as Y,IsCompatible FROM T
    UNION ALL
    SELECT Record2 as X,Record1 as Y,IsCompatible FROM T
) 

SELECT DISTINCT X,
  STUFF(
         (SELECT ',' + ISNULL(IsCompatible,'NULL')
          FROM (SELECT DISTINCT X as Y FROM T1) as Tbase
          LEFT JOIN T1 AS T2
               ON TBase.Y=T2.Y AND T1.X = T2.X
          ORDER BY TBase.Y
          FOR XML PATH ('')
          )
          , 1, 1, '')  AS COMPATABILITYSTRING
FROM T1
ORDER BY X

我喜欢将值实际输出为列而不是逗号分隔的字符串的选项，不过示例就是这样。实际上，可能有100多条记录需要交叉引用，因此需要动态构建列。这可能吗？第二个例子也是如此。如何做到这一点dynamically@StewartAlan：我已将查询添加到我的答案中，以创建变量维度的逗号分隔列表。如果您需要分离的列，那么这只能通过动态SQL完成。
;WITH T1 AS
(
    SELECT Record1 as X,Record2 as Y,IsCompatible FROM T
    UNION ALL
    SELECT Record2 as X,Record1 as Y,IsCompatible FROM T
) 

SELECT DISTINCT X,
  STUFF(
         (SELECT ',' + ISNULL(IsCompatible,'NULL')
          FROM (SELECT DISTINCT X as Y FROM T1) as Tbase
          LEFT JOIN T1 AS T2
               ON TBase.Y=T2.Y AND T1.X = T2.X
          ORDER BY TBase.Y
          FOR XML PATH ('')
          )
          , 1, 1, '')  AS COMPATABILITYSTRING
FROM T1
ORDER BY X