如何在嵌套集中查找特定level2节点的特定子级

admin

如何在嵌套集中查找特定level2节点的特定子级

sql

我有一个标准的嵌套集模型，每个节点都有名称，lft和rgt属性。

我可以使用以下方法找到特定员工的上司：

SELECT P2.* FROM Personnel AS P1, Personnel AS P2
WHERE P1.lft BETWEEN P2.lft AND P2.rgt
AND P1.name = "Bob"
ORDER BY P2.lft

我还可以通过添加限制和偏移量来找到level2管理器：

SELECT P2.* FROM Personnel AS P1, Personnel AS P2
WHERE P1.lft BETWEEN P2.lft AND P2.rgt
AND P1.name = "Bob"
ORDER BY P2.lft
LIMIT 2 OFFSET 1

在某些情况下，我可能有多个名为“鲍勃”的员工在不同的level2经理下工作。级别2管理员名称是唯一的。

我需要一个查询，该查询返回名为“ Susan”的level2经理的所有名为“ Bob”的员工。

编辑：我的查询只需要返回在“玛丽”下工作的“鲍勃”，因为他是唯一拥有名为“苏珊”的二级经理的鲍勃。

   Big Boss
   /      \
Brian   Susan
  |       |
Susan   Mary
  |       |
 Bob     Bob

阅读 153

2021-06-07

共1个答案

admin

将数字放入：

  1 Big Boss 14
   /        \
2 Brian 7  8 Susan 13
  |           |
3 Susan 6  9 Mary 12
  |           |
4 Bob 5    10 Bob 11

如果可以指定我们知道它的“ Susan”，8则：

SELECT employee.* 
FROM Personnel AS employee
inner join Personnel AS manager on employee.lft BETWEEN manager.lft
                                                    AND manager.rgt
WHERE 
  employee.name = 'Bob'
  and manager.name = 'Susan'
  and manager.lft = 8
ORDER BY employee.lft

否则，我认为您需要了解更多有关记录的信息，以指定您要说的是哪个经理。

select
  employee.*
from
  Personnel employee
  inner join 
    (SELECT node.name, node.lft, node.rgt, (COUNT(parent.name) - 1) AS depth
     FROM Personnel AS node
     inner join Personnel AS parent on node.lft BETWEEN parent.lft AND parent.rgt
     GROUP BY node.name, node.lft, node.rgt) as manager
                 on employee.lft between manager.lft and manager.rgt    
where
  employee.name = 'bob'
  and manager.name = 'susan'
  and manager.depth = 1

2021-06-07