分层结论sql

Question

我有数据库中的表和部门列表。

我写了这段代码：

WITH tree (Id, Name, Level)
AS
(
SELECT t.Id, t.Name, 0 AS Level
FROM DepartmentsT AS t WHERE t.ParentId IS NULL
UNION ALL
SELECT d.Id, d.Name, Level+1
FROM DepartmentsT AS d INNER JOIN tree ON tree.Id = d.ParentId
)

SELECT * FROM tree

我得到了

所以这里的问题。我如何制作“分层次”的唱片，我的意思是让孩子们在他们的父母面前展示，而不是他们现在的表现方式？现在，它们按其嵌套级别排序，简单的ORDER BY无法解决问题。希望得到你的帮助。

Answer 1

您可以在遍历树时保留此信息：

WITH tree (Id, Name, Level, parents) AS (
      SELECT t.Id, t.Name, 0 AS Level,
             cast(t.id as varchar(max)) as parents
      FROM DepartmentsT t
      WHERE t.ParentId IS NULL
      UNION ALL
      SELECT d.Id, d.Name, Level+1,
             tree.parents + '-->' + cast(d.id as varchar(max))
      FROM DepartmentsT d INNER JOIN
           tree
           ON tree.Id = d.ParentId
    )
SELECT id, name, level
FROM tree
ORDER BY parents;

注意：这假设id的长度都相同。