Question

我有以下问题：我有一个用于维护分层数据的表。我想在SQL 2005中使用CTE。

WITH tree (id, parentid, code, name) AS
(
    SELECT id, ofs.ParentID, ofs.code, ofs.name
      FROM OrganizationFeatures ofs
     WHERE ofs.ParentID IS NULL

    UNION ALL

    SELECT ofs.id, ofs.ParentID, ofs.code, ofs.name
      FROM OrganizationFeatures ofs
      JOIN tree ON tree.ID = ofs.ParentID
)

select * from tree

但是我想按代码排序，结果如下：

1
1/1
1/1/1
1/1/2
1/2/1
1/2/2
2
4/1

等。有任何想法吗？

Answer 1

要获取连接值，您需要在with。中执行此操作。

要进行排序，您需要在最后一次选择中添加一个订单。

WITH tree (id, parentid, code, name) AS
(
    SELECT id, ofs.ParentID, ofs.code, ofs.name
      FROM OrganizationFeatures ofs
     WHERE ofs.ParentID IS NULL

    UNION ALL

    SELECT ofs.id, ofs.ParentID, tree.code+'/'+ofs.code, ofs.name
      FROM OrganizationFeatures ofs
      JOIN tree ON tree.ID = ofs.ParentID
)

select * from tree order by code

此外，如果代码不是varchar，则必须转换此代码（tree.code+'/'+ofs.code）中的代码列才能生效。

Answer 2

Loki，我有类似的查询，但它并没有像我想要的那样排序，而是通过代码 - 它是星期五，我超载了。

无论如何，运行你的查询给了我一个错误，有必要施放;我必须按照以下方式改变它：

WITH tree (id, parentid, name, code) AS
(
    SELECT id, ofs.ParentID, ofs.name, CAST(ofs.name as varchar(255))
      FROM OrganizationFeatures ofs
     WHERE ofs.ParentID IS NULL

    UNION ALL

    SELECT ofs.id, ofs.ParentID, ofs.name, CAST(tree.code+'/'+ofs.name as varchar(255))
      FROM OrganizationFeatures ofs
      JOIN tree ON tree.ID = ofs.ParentID
)

select * from tree order by code

问题在于，尽管名称是varchar，但仍需要转换为varchar。对于大树，varchar（255）很可能是不够的。

所以我做了一个版本，上面提到的问题不是那么大：

WITH tree (id, parentid, name, code) AS
(
    SELECT id, ofs.ParentID, ofs.name, 
           CAST(ROW_NUMBER() OVER (ORDER BY ofs.name ASC) as varchar(255)) 
      FROM OrganizationFeatures ofs
     WHERE ofs.ParentID IS NULL

    UNION ALL

    SELECT ofs.id, ofs.ParentID, ofs.name, 
           CAST(tree.code +'/' + CAST(ROW_NUMBER() OVER (ORDER BY ofs.name ASC) as varchar(255)) as varchar(255))
      FROM OrganizationFeatures ofs
      JOIN tree ON tree.ID = ofs.ParentID
)

select * from tree order by code

但是我不喜欢这种解决方案需要施放。有没有更好的解决方案？

在SQL Server 2005中排序分层查询

2 个答案: