Question

我有下面的递归CTE：

DECLARE @T AS TABLE
(
    PARENT_TEST_ID int,
    TEST_ID  int,
    VALIDATED int,
    ERR int
)

INSERT INTO @T VALUES
(NULL, 1, 0, 0),
(NULL, 2, 0, 0),
(1,3,0, 0),
(1,4,0, 0),
(2,5,0, 0),
(2,6,0, 0),
(2,7,0, 0),
(7,8,0, 1)

;with C as
(
  select TEST_ID, PARENT_TEST_ID, (CASE WHEN ERR=1 THEN 0 ELSE 1 END) AS VALIDATED, ERR
  from @T
  where TEST_ID not in (select PARENT_TEST_ID 
                   from @T 
                   where PARENT_TEST_ID is not null) AND PARENT_TEST_ID IS NOT NULL
  union all
  select 
  T.TEST_ID, 
  T.PARENT_TEST_ID, 
  (case when t.TEST_ID=c.PARENT_TEST_ID and c.VALIDATED=1 AND T.ERR=0 THEN 1 ELSE 0 END) as VALIDATED,
  T.ERR
  from @T as T
    inner join C
      on T.TEST_ID = C.PARENT_TEST_ID 
)
SELECT DISTINCT PARENT_TEST_ID, TEST_ID, MIN(VALIDATED) FROM C
GROUP BY TEST_ID

但是我不能在结果SELECT中包含PARENT_TEST_ID列，因为它不是group by子句的一部分，所以我找到了这个链接：

Including column that is not part of the group by

所以现在我试图在我的情况下做同样的事情，我正在尝试应用John Woo解决方案，但我不知道如何。有帮助吗？还是其他任何最佳解决方案？

Answer 1

只需将您的最后一行更改为GROUP BY PARENT_TEST_ID, TEST_ID

您收到的错误告诉您，如果您不在其上聚合或按其分组其他聚合，则无法将列添加到输出中。通过将列添加到group by，您告诉SQL Server您希望通过父ID和测试ID值执行min。

rextester：http://rextester.com/JRF55398

Answer 2

iamdave是对的，但是如果你想从这个链接的答案中实现John Woo的解决方案，它将如下所示：

rextester：http://rextester.com/QQQGM79701

;with C as (
  select 
     test_id
   , parent_test_id
   , validated=(case when err = 1 then 0 else 1 end) 
   , err
  from @T as t
  where t.test_id not in (
    select i.parent_test_id
    from @T as i
    where i.parent_test_id is not null
    )
   and t.parent_test_id is not null
  union all
  select 
     t.test_id
   , t.parent_test_id
   , validated = case 
      when t.test_id = c.parent_test_id
        and c.validated = 1
        and t.err = 0 
      then 1 
      else 0 
      end
    , t.err
  from @T as T
    inner join c on t.test_id = c.parent_test_id
)
, r as (
  select 
     parent_test_id
   , test_id
   , Validated
   , rn = row_number() over (
        partition by test_id 
        order by Validated
    )
  from C
)
select 
     parent_test_id
   , test_id
   , Validated
  from r 
  where rn=1

HOWTO：包括不属于SQL SERVER中的聚合函数或Group by子句的列

2 个答案: