CTE 递归语句与自连接没有 ids

Question

我必须拆分数据列并与员工和经理建立关系。

Table ManagerDetails:

data	employee	manager
imp/imp2/imp3/imp4	imp2	notimp4
notimp1/notimp2/notimp3/notimp4	imp3	imp4

如果你观察下面的输出table，如果我取第一行imp4是imp3的经理，imp3是[=的经理14=]，imp2 是 imp 的经理，所以我需要构建 table，如下所述。

第一行的预期输出：

data	employee	manager
imp/imp2/imp3/imp4		imp4
imp/imp2/imp3	imp4	imp3
imp/imp2	imp3	imp2
imp	imp2	imp

我使用 CTE 以的引用拆分 ManagerDetails 行并进行查询

DECLARE @separator varchar(1) = '/';
WITH rCTE AS(
    SELECT
       1 as [level] ,
       d.data,
       CHARINDEX(@separator, CONCAT(d.data, @separator)) AS Position
    FROM ManagerDetails d   
    UNION ALL
    SELECT
       r.[level] + 1,
       r.data,
       CHARINDEX(@separator, CONCAT(r.data, @separator), r.Position + 1) AS Position
    FROM rCTE r
    WHERE CHARINDEX(@separator, CONCAT(r.data, @separator), r.Position + 1) > 0
)
SELECT [level], SUBSTRING(CONCAT(data, @separator), 1, Position - 1) AS [Value]
FROM rCTE
ORDER BY [level], Position DESC
OPTION (MAXRECURSION 0)

通过上述查询，我能够按预期显示数据列，但无法按预期更改经理和员工列。

感谢任何形式的帮助。

Answer 1

如果我理解正确，你只需要一个 LAG() 和分隔符在递归 CTE 中的位置：

Table:

CREATE TABLE ManagerDetails (id int, data varchar(1000))
INSERT INTO ManagerDetails (id, data)
VALUES 
   (1, 'imp/imp2/imp3/imp4'),
   (2, 'notimp1/notimp2/notimp3/notimp4')

声明：

DECLARE @separator varchar(1) = '/';
WITH rCTE AS(
    SELECT
       d.id,
       1 as [level] ,
       d.data,
       CAST(1 AS int) AS index1,
       CHARINDEX(@separator, CONCAT(d.data, @separator)) AS index2
    FROM ManagerDetails d   
    UNION ALL
    SELECT
       r.id,
       r.[level] + 1,
       r.data,
       CAST(r.index2 + LEN(@separator) AS int),
       CHARINDEX(@separator, CONCAT(r.data, @separator), r.index2 + 1)
    FROM rCTE r
    WHERE CHARINDEX(@separator, CONCAT(r.data, @separator), r.index2 + 1) > 0
)
SELECT
   id AS Id,
   SUBSTRING(CONCAT(data, @separator), 1, index2 - 1) AS [Value],
   LAG(SUBSTRING(CONCAT(data, @separator), index1, index2 - index1)) OVER (PARTITION BY id ORDER BY level DESC) AS [Manager],
   SUBSTRING(CONCAT(data, @separator), index1, index2 - index1) AS [Employee]
FROM rCTE
ORDER BY id, level DESC
OPTION (MAXRECURSION 0)

结果：

Id Value                           Manager Employee
---------------------------------------------------
1  imp/imp2/imp3/imp4                      imp4
1  imp/imp2/imp3                   imp4    imp3
1  imp/imp2                        imp3    imp2
1  imp                             imp2    imp
2  notimp1/notimp2/notimp3/notimp4         notimp4
2  notimp1/notimp2/notimp3         notimp4 notimp3
2  notimp1/notimp2                 notimp3 notimp2
2  notimp1                         notimp2 notimp1

CTE 递归语句与自连接没有 ids

CTE Recursion statement with self join without ids

tsql

sql-server

common-table-expression