Question

我的要求是编写一个sql查询来获取为managedobjects发生的子区域明智（故障）事件计数。我的数据库是postgres 8.4。让我解释一下使用表结构。

我在django的桌子： Managedobject：

class Managedobject(models.Model):
   name                = models.CharField(max_length=200, unique=True)
   iscontainer         = models.BooleanField(default=False,)
   parentkey           = models.ForeignKey('self', null=True)

活动表：

class Event(models.Model):
    Name        = models.CharField(verbose_name=_('Name'))
    foid        = models.ForeignKey(Managedobject)

Managedobject记录：

NOC
   Chennai
      MO_1
      MO_2
      MO_3
   Mumbai
      MO_4
      MO_5
      MO_6
   Delhi
   Bangalore
IP
   Calcutta
   Cochin

活动记录：

event1 MO_1
event2 MO_2
event3 MO_3
event4 MO_5
event5 MO_6

现在我需要获取所有子区域的事件计数。例如，

for NOC region:
  Chennai - 3
  Mumbai - 2
  Delhi - 0
  Bangalore - 0

到目前为止，我能够在两个不同的查询中获得结果。

获取子区域。

select id from managedobject where iscontainer = True and parentkey = 3489

对于每个区域（使用for循环），按如下方式获取计数：

SELECT count(*) 
from event ev 
WHERE ev.foid 
IN (
    WITH RECURSIVE q AS (
        SELECT h 
        FROM managedobject h 
        WHERE parentkey = 3489 
        UNION ALL 
        SELECT hi 
        FROM q 
        JOIN managedobject hi 
        ON hi.parentkey = (q.h).id 
    ) 
    SELECT (q.h).id FROM q
)

请帮助组合查询以使其成为单个查询并获取前5个区域。由于django中的查询很困难，我将进行原始的SQL查询。

Answer 1

我收到了查询：

WITH RECURSIVE q AS ( 
  SELECT  h, 
          1 AS level, 
          id AS ckey, 
          displayname as dname 
  FROM managedobject h 
  WHERE parentkey = 3489  
    and logicalnode=True 

 UNION ALL 

 SELECT  hi, 
         q.level + 1 AS level, 
         ckey, 
         dname 
 FROM q 
   JOIN managedobject hi ON hi.parentkey = (q.h).id 
) 
SELECT count(ckey) as ccount, 
       ckey, 
       dname 
FROM q 
  JOIN event as ev on ev.foid_id = (q.h).id 
GROUP BY ckey, dname 
ORDER BY ccount DESC 
LIMIT 5

Postgres递归查询+分组+加入Django

1 个答案: