Sql Server使用相同字段的递归父/子表

Question

我需要让父母和所有孩子都来自同一张桌子......

运行此查询时：

select location, children  from lochierarchy where parent ='HSAGCF'

结果：

Location    Children
--------    ------------
HSAGCFSMF   1
HSAGEE      1
HSAGGAI     0
HSAGPO      1
HSAGSA      1
HSAGSACC    1
HSAGSAFR    0
HSAGSARV    0
HSAGSASG    0
HSAGSC      1
HSAGSD      1
HSAGSI      1
HSAGSO      1
HSAGSR      0
HSAGST      0
HSAGSTTO    0

当地点有子项= 1时，层次结构中有更多子项

如何进行递归，将每个位置的查询放在上面的子句= 1的位置，然后再次运行查询：

select location 
  from lochierarchy 
 where parent in ( 'HSAGCFSMF', 'HSAGEE', 'HSAGGAI', 'HSAGPO', 'HSAGSA',
                   'HSAGSACC','HSAGSAFR', 'HSAGSARV', 'HSAGSASG', 'HSAGSC',
                   'HSAGSD', 'HSAGSI', 'HSAGSO', 'HSAGSR', 'HSAGST', 
                   'HSAGSTTO', 'HSAGSV', 'HSAGU1', 'HSAGU2', 'HSAGU3', 'HSAGU4')


locations     Children
----------    ------------
HSAGCFSMF       1
HSAGEE          1
HSAGGAI         0
HSAGPO          1
HSAGSA          1
HSAGSACC        1
HSAGSAFR        0
HSAGSARV        0
HSAGSASG        0
HSAGSC          1
HSAGSD          1
HSAGSI          1
HSAGSO          1
HSAGSR          0
HSAGST          0
HSAGSTTO        0
HSAGSV          0

这个递归需要重复，直到所有位置的孩子都是= 0

Answer 1

如果您使用的是SQL 2005或更高版本，则可以使用递归公用表表达式。像这样：

declare @parent varchar(20) = 'HSAGCF';

with cte as (
   select location, parent 
   from lochierarchy
   where location = @parent

   union all

   select c.location, c.parent
   from lochierarchy as c
   join cte as p
      on c.parent = p.location
)
select *
from cte;

如果你想要树中叶子节点的路径，我把它留给读者练习。