SQL 从自引用中按父子顺序检索父子关系 table

Question

我使用以下查询从自引用父项的 table 中检索父子关系数据。

    -- go down the hierarchy and get the childs
    WITH ChildLocations(LocationId, FkParentLocationId, [Level]) 
        AS 
        (
            (
                -- Start CTE off by selecting the home location of the user
                SELECT l.LocationId, l.FkParentLocationId, 0 as [Level]
                FROM   Location l
                WHERE  l.LocationId = @locationId
            )
            UNION ALL 
            -- Recursively add locations that are children of records already found in previous iterations.
            SELECT l2.LocationId, l2.FkParentLocationId, [Level] + 1
            FROM   ChildLocations tmp
                   INNER JOIN Location l2
                        ON  l2.FkParentLocationId = tmp.LocationId
        )
    INSERT INTO @tmp
    SELECT * from ChildLocations;

table有以下字段： LocationId、FkParentLocationId、FkLocationTypeId 等...

这工作正常，但我想检索它的方式如下：

Parent 1
    Child 1
    Child 2
      Child 21
    Child 3
      Child 31
Parent 2
    Child 4
    Child 5
    Child 6

目前给出的是这样的：

Parent 1
Parent 2
    Child 1
    Child 2
    Child 3
    Child 4
 etc....

我如何修改上面的内容以按我想要的顺序获取它。

Answer 1

如何附加一个 'order' 字段？这可能是一种方法：

WITH ChildLocations(LocationId, FkParentLocationId, [Level]) 
    AS 
    (
        (
            -- Start CTE off by selecting the home location of the user
            SELECT l.LocationId, l.FkParentLocationId, 0 as [Level],
                   cast( str( l.locationId ) as varchar(max) ) as orderField
            FROM   Location l
            WHERE  l.LocationId = @locationId
        )
        UNION ALL 
        -- Recursively add locations that are children ...
        SELECT l2.LocationId, l2.FkParentLocationId, [Level] + 1,
               tmp.orderField + '-' + 
               str(tmp.locationId) as orderField
        FROM   ChildLocations tmp
               INNER JOIN Location l2
                    ON  l2.FkParentLocationId = tmp.LocationId
    )
SELECT * from ChildLocations order by orderField;

请记住，Order by 在 Insert 中是不允许的。

Take a look a sample

SQL 从自引用中按父子顺序检索父子关系 table

SQL to retrieve parent-child relationship in parent-child order, from a self referencing table

sql

hierarchy