SQL ORDER BY 有例外

Question

我想按 3 列（优先级、预期日期、创建日期）对（子 select 的结果）进行排序，但是对于几行排序应该以不同的方式工作。
很难用文字描述所以我准备了一张图片：

列排名在之前 table 现在是：

ROW_NUMBER() OVER(ORDER BY Priority DESC, ExpectedDate DESC, CreateDate ASC) AS [Rank],

如您所见，ShouldBeAfter 列指示 ID，无论排序如何，该行都应始终出现在该行之后。

如何编写查询以达到After的状态？

编辑 1：
示例数据：

DECLARE @Queue TABLE 
(
    [ChildID] INT,
    [ParentID] INT,
    [No] INT,
    [Change] INT,
    [Priority] INT,
    [ExpectedDate] DATETIME,
    [CreateDate] DATETIME
)

INSERT INTO @Queue VALUES (242,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-11-27 15:08:40.677')
INSERT INTO @Queue VALUES (243, 274, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-11-27 15:22:46.350')
INSERT INTO @Queue VALUES (244,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-11-27 15:29:52.010')
INSERT INTO @Queue VALUES (259,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-11-30 15:54:48.710')
INSERT INTO @Queue VALUES (261,   0, 0, 0,  4, '1900-01-01 00:00:00.000', '2015-12-01 11:07:32.357')
INSERT INTO @Queue VALUES (263,   0, 0, 0,  5, '1900-01-01 00:00:00.000', '2015-12-02 12:07:01.980')
INSERT INTO @Queue VALUES (264,   0, 0, 0,  2, '1900-01-01 00:00:00.000', '2015-12-03 14:58:19.717')
INSERT INTO @Queue VALUES (266,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-08 09:55:06.277')
INSERT INTO @Queue VALUES (269,   0, 0, 0,  3, '2015-12-16 00:00:00.000', '2015-12-08 17:53:24.820')
INSERT INTO @Queue VALUES (270,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-09 15:50:37.970')
INSERT INTO @Queue VALUES (272,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-11 12:06:19.253')
INSERT INTO @Queue VALUES (273, 242, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-11 12:08:20.010')
INSERT INTO @Queue VALUES (274,   0, 0, 0,  2, '1900-01-01 00:00:00.000', '2015-12-11 12:09:00.200')
INSERT INTO @Queue VALUES (275,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-11 12:14:50.110')
INSERT INTO @Queue VALUES (276,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-11 12:17:49.220')
INSERT INTO @Queue VALUES (277,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-11 12:24:28.823')
INSERT INTO @Queue VALUES (278,   0, 0, 0,  5, '2015-12-10 00:00:00.000', '2015-12-11 12:27:53.803')
INSERT INTO @Queue VALUES (279,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-11 12:32:14.397')
INSERT INTO @Queue VALUES (280,   0, 0, 0,  2, '1900-01-01 00:00:00.000', '2015-12-11 13:56:06.080')
INSERT INTO @Queue VALUES (281,   0, 0, 0,  2, '1900-01-01 00:00:00.000', '2015-12-15 10:16:35.057')
INSERT INTO @Queue VALUES (282, 276, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-15 10:18:50.180')
INSERT INTO @Queue VALUES (284,   0, 0, 0,  3, '1900-01-01 00:00:00.000', '2015-12-15 11:33:33.553')

Answer 1

这有点麻烦，因为您需要一个额外的连接：

select t.*
from t left join
     t2
     on t.id = t2.shouldbeafter
order by coalesce(t2.shouldbeafter, t.id),
         t.shouldbeafter, t.id;

注意：这适用于一个级别，但不适用于多个级别。

Answer 2

您可以使用 CTE 分两步完成：

;WITH InitialRank AS (
SELECT *,
       ROW_NUMBER() OVER(ORDER BY Priority DESC, 
                                  ExpectedDate DESC, 
                                  CreateDate ASC) AS [Rank]
FROM Queue
), FinalRank AS (
SELECT t1.ID, t1.ShouldBeAfter, t1.No, t1.Change,
       t1.Priority, t1.ExpectedDate, t1.CreateDate,
       COALESCE(CAST(t2.Rank AS DECIMAL(4,1)) + 0.5, t1.Rank) AS Rank
FROM InitialRank AS t1
LEFT JOIN InitialRank AS t2 
ON t1.ShouldBeAfter <> 0 AND t1.ShouldBeAfter = t2.ID
)
SELECT ID, ShouldBeAfter, No, Change,
       Priority, ExpectedDate, CreateDate,
       ROW_NUMBER() OVER (ORDER BY Rank) AS Rank
FROM FinalRank
ORDER BY Rank

第一步计算由 3 列 (Priority, ExpectedDate, CreateDate) 定义的 'initial' 排名。
第二步更改具有非零 ShouldBeAfter 值的所有行的排名：排名的新值是 'comes before' 行的排名加上 0.5 ，因此该行将排在之后 'comes before' 行。

注意：只要只有单级依赖项，上面的方法就可以工作。

Demo here

Answer 3

无需显式连接即可完成相同操作的另一种方法：

SELECT *,
  MIN(CASE WHEN ShouldBeAfter = 0 THEN PreRank END)
    OVER(PARTITION BY CASE WHEN ShouldBeAfter = 0 THEN ID ELSE ShouldBeAfter END) AS [Rank]
FROM (
  SELECT *,
    ROW_NUMBER() OVER(ORDER BY Priority DESC, ExpectedDate DESC, CreateDate ASC) AS [PreRank]
  FROM Queue
)A
ORDER BY [Rank], ShouldBeAfter

Demo here

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