Иерархические данные с CTE

Question

Прошу прощения, если ответ уже опубликован, но я не смог найти ответ даже после поиска.

У меня есть следующая таблица

CREATE TABLE [dbo].[emp](
    [id] [int] NOT NULL, 
    [name] [varchar](20) NULL, 
    [mgrid] [int] NULL 
) ON [PRIMARY] 

С данными

INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (1, N'a', 0) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (2, N'a1', 1) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (3, N'a11', 2) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (4, N'a12', 2) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (5, N'a13', 2) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (6, N'a2', 1) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (7, N'a3', 1) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (8, N'a31', 7) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (9, N'a32', 7) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (10, N'b', 0) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (11, N'b1', 10) 
INSERT [dbo].[emp] ([id], [name], [mgrid]) VALUES (12, N'b2', 10) 

И я хотел бы следующий вывод

a 
    a1 
     a11 
     a12 
     a13 
    a2 
    a3 
     a31 
     a32 
b 
    b1 
    b2 

Возможно ли это в SQL Server?

Answer 1

SQLFiddle demo

Вы можете использовать '' вместо '+' в последней строке для ввода строки.

with t as 
(
    select id,name,mgrid,1 as level,cast(name as varchar(max)) as path 
     from emp where mgrid=0 
    union all 
    select emp.id,emp.name,emp.mgrid, t.level+1 as level, 
     t.path+cast(emp.name as varchar(max)) as path 

    from emp 
    join t on emp.mgrid=t.id 
) 

select replicate('+', level)+name from t order by path 

Answer 2

with CTE as 
(
    select * 
    , level = 1 
    from emp 
    where mgrid = 0 
    union all 
    select emp.id, 
    name = cast(space((level) * 3) + emp.name as varchar(20)), 
    emp.mgrid, 
    level = level + 1 
    from emp 
    inner join CTE on CTE.id = emp.mgrid 
) 
select name 
from CTE 
order by ltrim(name) 

Answer 3

Вы можете использовать (выражение таблицы Comnon для достижения этой цели) КТР

проверить этот пример кода:

declare @emp table(
    [id] [int] NOT NULL, 
    [name] [varchar](20) NULL, 
    [mgrid] [int] NULL 
) 


INSERT @emp ([id], [name], [mgrid]) VALUES (1, N'a', 0) 
INSERT @emp ([id], [name], [mgrid]) VALUES (2, N'a1', 1) 
INSERT @emp ([id], [name], [mgrid]) VALUES (3, N'a11', 2) 
INSERT @emp ([id], [name], [mgrid]) VALUES (4, N'a12', 2) 
INSERT @emp ([id], [name], [mgrid]) VALUES (5, N'a13', 2) 
INSERT @emp ([id], [name], [mgrid]) VALUES (6, N'a2', 1) 
INSERT @emp ([id], [name], [mgrid]) VALUES (7, N'a3', 1) 
INSERT @emp ([id], [name], [mgrid]) VALUES (8, N'a31', 7) 
INSERT @emp ([id], [name], [mgrid]) VALUES (9, N'a32', 7) 
INSERT @emp ([id], [name], [mgrid]) VALUES (10, N'b', 0) 
INSERT @emp ([id], [name], [mgrid]) VALUES (11, N'b1', 10) 
INSERT @emp ([id], [name], [mgrid]) VALUES (12, N'b2', 10); 


with cte (id,name, MGRID) as 
(
    select id, name,MGRID 
    from @emp 
    union all 
    select c.id, c.name, c.MGRID 
    from @emp c 
    inner join cte p 
     on c.mgrid = P.id 
) 


SELECT Distinct * FROM CTE 

Answer 4

WITH RCTE AS 
(
    SELECT id, name, mgrid, CAST('' AS NVARCHAR(MAX)) AS blanks , CAST(name AS NVARCHAR(MAX)) AS ordr 
    FROM dbo.emp WHERE mgrid = 0 

    UNION ALL 

    SELECT e.id, e.name, e.mgrid, blanks + ' ' AS blanks, ordr + e.name AS ordr 
    FROM dbo.emp e 
    INNER JOIN RCTE r ON e.mgrid = r.id 
) 
SELECT blanks + name FROM RCTE 
ORDER BY ordr 

Answer 5

Запрос:

DECLARE @temp TABLE 
(
    [id] [int] NOT NULL, 
    [name] [varchar](20) NULL, 
    [mgrid] [int] NULL 
) 

INSERT INTO @temp ([id], [name], [mgrid]) 
VALUES 
    (1, N'a', 0), (2, N'a1', 1), 
    (3, N'a11', 2), (4, N'a12', 2), 
    (5, N'a13', 2), (6, N'a2', 1), 
    (7, N'a3', 1), (8, N'a31', 7), 
    (9, N'a32', 7), (10, N'b', 0), 
    (11, N'b1', 10), (12, N'b2', 10) 

DECLARE @out VARCHAR(MAX) = '' 

;WITH cte AS 
(
    SELECT *, Lvl = 0, nn = CAST(name AS VARCHAR(MAX)) 
    FROM @temp 
    WHERE mgrid = 0 

    UNION ALL 

    SELECT t.*, c.Lvl + 1, nn = CAST(REPLICATE(' ', c.Lvl + 1) + t.name AS VARCHAR(MAX)) 
    FROM @temp t 
    JOIN cte c ON c.id = t.mgrid 
) 
SELECT @out = (
    SELECT nn + CHAR(13) 
    FROM cte 
    ORDER BY LTRIM(nn) 
    FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)') 

PRINT @out 

Выход:

a 
    a1 
     a11 
     a12 
     a13 
    a2 
    a3 
     a31 
     a32 
b 
    b1 
    b2