Question

这是关于Sorting based on next and previous records in SQL

的后续问题

但现在它变得有点复杂，例如：

如果任何1的字母与2的任何字母匹配，我想更改顺序，以便该字母与以下记录匹配。
如果未找到匹配项，则应按字母顺序排序。
ID可能不会成功，并且记录不会以正确的顺序存储。 [SQLFiddle Demo]

create table Parent (
id [bigint] IDENTITY(1,2), 
number bigint NOT NULL,
PRIMARY KEY (id)
)
GO

create table Child (
id [bigint] IDENTITY(1,2), 
parentId BIGINT, 
letter VARCHAR(1) NOT NULL,
PRIMARY KEY (id),
UNIQUE (parentId, Letter),
FOREIGN KEY (parentId) REFERENCES Parent(id)
)
GO

DECLARE @ParentIdentity BIGINT

INSERT Parent (number) VALUES (2)
SET @ParentIdentity = @@IDENTITY
INSERT Child (parentId, letter) VALUES (@ParentIdentity, 'C')
INSERT Child (parentId, letter) VALUES (@ParentIdentity, 'B')

INSERT Parent (number) VALUES (3)
SET @ParentIdentity = @@IDENTITY
INSERT Child (parentId, letter) VALUES (@ParentIdentity, 'D')
INSERT Child (parentId, letter) VALUES (@ParentIdentity, 'B')

INSERT Parent (number) VALUES (1)
SET @ParentIdentity = @@IDENTITY
INSERT Child (parentId, letter) VALUES (@ParentIdentity, 'C')
INSERT Child (parentId, letter) VALUES (@ParentIdentity, 'A')
GO

当前查询
目前我正在使用此查询进行排序：

;WITH CTE AS 
(
SELECT id,ParentID,letter,

ROW_NUMBER() OVER (ORDER BY ID) seq_id,
ROW_NUMBER() OVER (PARTITION BY parentId ORDER BY ID) first_element,
ROW_NUMBER() OVER (PARTITION BY parentId ORDER BY ID DESC) Last_element
FROM Child
), CTE2 AS 
(
SELECT c1.id, c1.parentid, c1.letter, c2.parentid as c2parentid
FROM CTE c1
INNER JOIN CTE c2
ON c1.last_element = 1
AND c2.first_element = 1
AND c1.seq_id + 1 = c2.seq_id
), CTE3 AS 
(
SELECT C.parentid, C.id
FROM CTE2
INNER JOIN child C ON CTE2.c2parentid = C.parentid
AND C.letter = CTE2.letter
)
SELECT P.number, C.letter
FROM Child C
JOIN Parent P ON C.parentId = P.id
LEFT JOIN CTE3 ON CTE3.id = C.id
ORDER BY P.number, ISNULL(CTE3.id,0) DESC, C.letter

当前结果集

number               letter
-------------------- ------
1                    A
1                    C
2                    B
2                    C
3                    B
3                    D

预期结果集
为了澄清我实际想做的事情，这里是预期的结果集：

number               letter
-------------------- ------
1                    A
1                    C
2                    C 
2                    B 
3                    B
3                    D

其他要求和问题

必须在 SQL Server 2005 中工作。
有一个场景，每个号码使用3个字母，如果它只使用最佳匹配，我很高兴。

有人能指出我如何处理这种情况的正确方向吗？

Answer 1

如果我理解您的要求是正确的，那么您有letter的某些部分，并且您希望每个部分都以前一部分中的letter开头并以;WITH t AS ( SELECT c.id, c.parentId, c.letter, dt.parentSeq FROM Child c JOIN ( SELECT ci.parentId, ROW_NUMBER() OVER (ORDER BY p.number) parentSeq FROM Child ci JOIN Parent p ON ci.parentId = p.id GROUP BY ci.parentId, p.number) dt ON c.parentId = dt.parentId ) SELECT p.number, t.letter FROM t JOIN Parent p ON t.parentId = p.id ORDER BY p.number, CASE WHEN t.letter IN (SELECT ti.letter FROM t ti WHERE ti.parentSeq = t.parentSeq - 1) THEN 0 WHEN t.letter IN (SELECT ti.letter FROM t ti WHERE ti.parentSeq = t.parentSeq + 1) THEN 2 ELSE 1 END, t.letter s结尾在下一部分，如果是，试试这个：

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Answer 2

我不确定这是否适用于某些复杂的实际数据，但您可以查看：

;WITH cte AS(SELECT  ci.id, ci.parentId, ci.letter, p.number, 
                     DENSE_RANK() OVER (ORDER BY p.number) rn
             FROM  Child ci
             JOIN Parent p ON ci.parentId = p.id)
SELECT t1.number, t1.letter
FROM cte t1
LEFT JOIN cte t2 ON t2.rn = t1.rn - 1 AND t1.letter = t2.letter
LEFT JOIN cte t3 ON t1.rn = t3.rn - 1 AND t1.letter = t3.letter
ORDER BY t1.number, t1.letter + t2.letter DESC, t1.letter + t3.letter, t1.letter

如果这不起作用，您可以切换到@ shA.t的巧妙排序：

;WITH cte AS(SELECT  ci.id, ci.parentId, ci.letter, p.number, 
                     DENSE_RANK() OVER (ORDER BY p.number) rn
             FROM  Child ci
             JOIN Parent p ON ci.parentId = p.id)
SELECT number, letter
FROM cte 
ORDER BY
    number,
    CASE WHEN letter IN (SELECT ti.letter FROM cte ti WHERE ti.rn = cte.rn - 1) THEN 0 
        WHEN letter IN (SELECT ti.letter FROM cte ti WHERE ti.rn = cte.rn + 1) THEN 2 
        ELSE 1 END,
    letter

Answer 3

我使用Row_Number函数来解决这个问题，我希望它可以帮到你。

SELECT Number, Letter 
FROM (
    SELECT number, letter, ROW_NUMBER()over(Partition by letter,Number order by Number) as R 
    FROM Child C 
      JOIN Parent P 
      ON P.id = C.parentId) x 
ORDER BY number, R desc

基于SQL中下一个和上一个记录的复杂排序

3 个答案: