Создать представление на основе иерархии/используется CTE

Question

Возможно ли создать представление на основе иерархии/cte?

Я видел пример того, как сгенерировать набор результатов по ссылке recursive query.
Я приложил ddl и заявление.

Спасибо,
Элмера

CREATE TABLE [dbo].[XHR_PERSON](
[PERSON_ID] [bigint] NOT NULL, 
[LAST_NAME] [varchar](100) NOT NULL, 
[FIRST_NAME] [varchar](100) 
,EFFECTIVE_START_DATE Date 
,EFFECTIVE_END_DATE Date) 

CREATE TABLE [dbo].[XHR_EMPLOYMENT](
[PERSON_ID] [bigint] NOT NULL, 
[EMPLOYEE_NUMBER] [varchar](100) NULL, 
[SUPERVISOR_ID] [bigint] NULL 
,EFFECTIVE_START_DATE Date 
,EFFECTIVE_END_DATE Date) 

insert into XHR_PERSON 
select 1, 'SMY', null, '1990-01-01','9999-12-31' UNION ALL 
select 2, 'JSB',null, '1990-01-01','9999-12-31' union all 
select 3, 'LFG',null, '1990-01-01','9999-12-31' union all 
select 4, 'Elmer',null, '1990-01-01','9999-12-31' union all 
select 5, 'Jon',null, '1990-01-01','9999-12-31' union all 
select 6, 'Anne',null, '1990-01-01','9999-12-31' union all 
select 7, 'Teddy',null, '1990-01-01','9999-12-31' union all 
select 8, 'Alex',null , '1990-01-01','9999-12-31'union all 
select 9, 'Jeff',null, '1990-01-01','9999-12-31' 
update XHR_PERSON set first_name = 'A' 

insert into XHR_EMPLOYMENT 
select 1, '111',null, '1990-01-01','9999-12-31' UNION ALL 
select 2, '222',1, '1990-01-01','9999-12-31' union all 
select 3, '333',1, '1990-01-01','9999-12-31' union all 
select 4, '444',2, '1990-01-01','9999-12-31' union all 
select 5, '555',2, '1990-01-01','9999-12-31' union all 
select 6, '666',4, '1990-01-01','9999-12-31' union all 
select 7, '777',3, '1990-01-01','9999-12-31' union all 
select 8, '888',3, '1990-01-01','9999-12-31' union all 
select 9, '999',8, '1990-01-01','9999-12-31' 


CREATE VIEW dbo.HR_DIRECTREPORTSV as 
WITH xxDirectReports (Supervisor_id, Person_id, Employee_number, Employee_name, Supervisor_Empno, Supervisor_Name, Level1) 

AS 
(
SELECT hre.Supervisor_id 
    ,hre.Person_id 
    ,hre.Employee_number 
    ,hrp.last_name+', '+hrp.first_name Employee_Name 
    ,hrpx.employee_number  Supervisor_Empno 
    ,hrpx.fullname   Supervisor_Name 
    ,0 AS Level1 
FROM dbo.xhr_employment AS hre left join (select hrp1.person_id,hre1.employee_number             ,(hrp1.last_name+', '+hrp1.first_name) as fullname 
              from dbo.xHR_PERSON hrp1 
               ,dbo.xhr_employment hre1 
              where hrp1.person_id = hre1.person_id 
              AND getdate() between hrp1.effective_start_date 
                  and hrp1.effective_end_date 
             ) hrpx on hre.supervisor_id = hrpx.person_id 
    ,dbo.xHR_PERSON  AS hrp 
WHERE hre.person_id = hrp.person_id 
AND GETDATE() between hrp.effective_start_date and hrp.effective_end_date 
AND GETDATE() between hrp.effective_start_date and hrp.effective_end_date 
--AND hrpx.person_id = 1 
UNION ALL 
SELECT hre.Supervisor_id 
     ,hre.Person_id 
     ,hre.Employee_number 
     ,hrp.last_name+', '+hrp.first_name Employee_Name 
     ,hrpx.employee_number    Supervisor_Empno 
     ,hrpx.fullname      Supervisor_Name 
     ,Level1+1 
FROM dbo.xhr_employment AS hre inner join (select hrp1.person_id  
               ,hre1.employee_number 
               ,(hrp1.last_name+', '+hrp1.first_name) as fullname 
              from dbo.xHR_PERSON hrp1 
               ,dbo.xhr_employment hre1 
              where hrp1.person_id = hre1.person_id 
              AND getdate() between hrp1.effective_start_date 
                  and hrp1.effective_end_date 
             ) hrpx on hre.supervisor_id = hrpx.person_id 
           INNER JOIN xxDirectReports AS xx ON hre.Supervisor_id = xx.Person_id 
    ,dbo.xHR_PERSON  AS hrp 
WHERE hre.person_id = hrp.person_id 
AND GETDATE() between hrp.effective_start_date and hrp.effective_end_date 
AND GETDATE() between hrp.effective_start_date and hrp.effective_end_date) 

Answer 1

После WITH были указаны (за закрывающую скобку), вам необходимо выбрать все значения из CTE:

select * from xxDirectReports 

Это фактический запрос выбора, который представляет собой представление.

Это полный рабочий пример, с возможностью выбора окончательного вывода представления, а также некоторые дополнительные GO заявления, чтобы заявления, которые будут работать в одном исполнении в SQL Server Management Studio:

if not OBJECT_ID('XHR_PERSON', 'Table') is null drop table XHR_PERSON 
if not OBJECT_ID('XHR_EMPLOYMENT', 'Table') is null drop table XHR_EMPLOYMENT 
if not OBJECT_ID('HR_DIRECTREPORTSV', 'View') is null drop view HR_DIRECTREPORTSV 

CREATE TABLE [dbo].[XHR_PERSON](
[PERSON_ID] [bigint] NOT NULL, 
[LAST_NAME] [varchar](100) NOT NULL, 
[FIRST_NAME] [varchar](100) 
,EFFECTIVE_START_DATE Date 
,EFFECTIVE_END_DATE Date) 

CREATE TABLE [dbo].[XHR_EMPLOYMENT](
[PERSON_ID] [bigint] NOT NULL, 
[EMPLOYEE_NUMBER] [varchar](100) NULL, 
[SUPERVISOR_ID] [bigint] NULL 
,EFFECTIVE_START_DATE Date 
,EFFECTIVE_END_DATE Date) 

insert into XHR_PERSON 
select 1, 'SMY', null, '1990-01-01','9999-12-31' UNION ALL 
select 2, 'JSB',null, '1990-01-01','9999-12-31' union all 
select 3, 'LFG',null, '1990-01-01','9999-12-31' union all 
select 4, 'Elmer',null, '1990-01-01','9999-12-31' union all 
select 5, 'Jon',null, '1990-01-01','9999-12-31' union all 
select 6, 'Anne',null, '1990-01-01','9999-12-31' union all 
select 7, 'Teddy',null, '1990-01-01','9999-12-31' union all 
select 8, 'Alex',null , '1990-01-01','9999-12-31'union all 
select 9, 'Jeff',null, '1990-01-01','9999-12-31' 
update XHR_PERSON set first_name = 'A' 

insert into XHR_EMPLOYMENT 
select 1, '111',null, '1990-01-01','9999-12-31' UNION ALL 
select 2, '222',1, '1990-01-01','9999-12-31' union all 
select 3, '333',1, '1990-01-01','9999-12-31' union all 
select 4, '444',2, '1990-01-01','9999-12-31' union all 
select 5, '555',2, '1990-01-01','9999-12-31' union all 
select 6, '666',4, '1990-01-01','9999-12-31' union all 
select 7, '777',3, '1990-01-01','9999-12-31' union all 
select 8, '888',3, '1990-01-01','9999-12-31' union all 
select 9, '999',8, '1990-01-01','9999-12-31'; 

GO 
CREATE VIEW dbo.HR_DIRECTREPORTSV as 
WITH xxDirectReports (Supervisor_id, Person_id, Employee_number, Employee_name, Supervisor_Empno, Supervisor_Name, Level1) 
AS 
(
SELECT hre.Supervisor_id 
    ,hre.Person_id 
    ,hre.Employee_number 
    ,hrp.last_name+', '+hrp.first_name Employee_Name 
    ,hrpx.employee_number  Supervisor_Empno 
    ,hrpx.fullname   Supervisor_Name 
    ,0 AS Level1 
FROM dbo.xhr_employment AS hre left join (select hrp1.person_id,hre1.employee_number             ,(hrp1.last_name+', '+hrp1.first_name) as fullname 
              from dbo.xHR_PERSON hrp1 
               ,dbo.xhr_employment hre1 
              where hrp1.person_id = hre1.person_id 
              AND getdate() between hrp1.effective_start_date 
                  and hrp1.effective_end_date 
             ) hrpx on hre.supervisor_id = hrpx.person_id 
    ,dbo.xHR_PERSON  AS hrp 
WHERE hre.person_id = hrp.person_id 
AND GETDATE() between hrp.effective_start_date and hrp.effective_end_date 
AND GETDATE() between hrp.effective_start_date and hrp.effective_end_date 
--AND hrpx.person_id = 1 
UNION ALL 
SELECT hre.Supervisor_id 
     ,hre.Person_id 
     ,hre.Employee_number 
     ,hrp.last_name+', '+hrp.first_name Employee_Name 
     ,hrpx.employee_number    Supervisor_Empno 
     ,hrpx.fullname      Supervisor_Name 
     ,Level1+1 
FROM dbo.xhr_employment AS hre inner join (select hrp1.person_id  
               ,hre1.employee_number 
               ,(hrp1.last_name+', '+hrp1.first_name) as fullname 
              from dbo.xHR_PERSON hrp1 
               ,dbo.xhr_employment hre1 
              where hrp1.person_id = hre1.person_id 
              AND getdate() between hrp1.effective_start_date 
                  and hrp1.effective_end_date 
             ) hrpx on hre.supervisor_id = hrpx.person_id 
           INNER JOIN xxDirectReports AS xx ON hre.Supervisor_id = xx.Person_id 
    ,dbo.xHR_PERSON  AS hrp 

WHERE hre.person_id = hrp.person_id 
AND GETDATE() between hrp.effective_start_date and hrp.effective_end_date 
AND GETDATE() between hrp.effective_start_date and hrp.effective_end_date) 
select * from xxDirectReports; 

GO 
select * from HR_DIRECTREPORTSV; 

Обновление:

Кроме того, можно ли принести записи, которая начинается с, на основе выборки данных, биогаз, а не с SMy?

Да! Хотя подход меняется. Я бы порекомендовал иметь переменную в операторе привязки CTE, а вместо того, чтобы иметь представление, создайте ее как функцию с табличным значением. Однако существует несколько разных способов выбора иерархических данных, как только предполагается, что это иерархическая форма ... одним из подходов является Иерархический путь.

Чтобы добавить это поведение, добавьте его имя в Path столбца в предложении WITH, и добавить следующее, во-первых, в заявлении якорной:

convert(nvarchar(256), RTRIM(convert(nvarchar(12), hre.PERSON_ID))) Path 

А во-вторых, в рекурсивном утверждении:

convert(nvarchar(256), rtrim(Path) + '.' + RTRIM(convert(nvarchar(12), hre.PERSON_ID))) Path 

Затем, чтобы выбрать корень иерархии (LFG) и все подчиненные, просто измените запрос, который выбирает из вида на это:

select * from HR_DIRECTREPORTSV 
where Path = '3' or Path like '3.%' 

Результаты таковы:

Path Supervisor_id Person_id Employee_number Employee_name Supervisor_Empno Supervisor_Name Level1 
3 1 3 333 LFG, A 111 SMY, A 0 
3.7 3 7 777 Teddy, A 333 LFG, A 1 
3.8 3 8 888 Alex, A 333 LFG, A 1 
3.8.9 8 9 999 Jeff, A 888 Alex, A 2 

Answer 2

Да, вы можете - что-то вроде

CREATE VIEW [mySchema].vwItem 
AS 
    WITH cteItem  
    AS  
    ( 
     SELECT  
     item_id  AS 'ItemID',  
     item_level AS 'ItemLevel',  
     item_number_type AS 'ItemNumberType',  
     CASE item_level  
      WHEN 1 THEN item_id  
      WHEN 2 THEN item_parent_id  
      WHEN 3 THEN item_grandparent_id 
     ELSE item_id  
     END  AS 'ItemParent',  
     FROM  
     [mySchema].[ITEM] 
    )  

    SELECT  
     child.*,  
     parent.item_id AS 'ParentId',  
     parent.desc AS 'ParentDescription'  
    FROM  
     cteItem child 
    LEFT OUTER JOIN [mySchema].[ITEM] parent ON  
     child.ItemParent = parent.item_id