根据SQL中的下一个和上一个记录进行复杂的排序

Nick N. 发表于 Dev

尼克·N。

但是现在变得更加复杂了，例如：

如果1个字母与2个字母匹配，我想更改顺序，以便该字母与以下记录匹配。
如果找不到匹配项，则应按字母正常排序。
这些ID可能不会成功，并且记录的顺序也不正确。[SQLFiddle演示]

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
当前正在对此查询进行排序：

;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
为了阐明我的实际意图，以下是预期结果集：

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

其他要求和问题

它必须在SQL Server 2005中工作。
有一种情况，每个数字使用3个字母，如果它只使用最佳匹配，我会感到高兴。

谁能为我指出如何应对这种情况的正确方向？

如果我理解您的要求正确，那么您有的某些部分，parentId并且您希望每个部分都以letters在上一部分中开始，以sletter在下一部分中结束，如果是，请尝试以下操作：

;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