Question

我希望用基于表中数据的模式值替换NULL值。

在下面的示例中，我想将EquipmentID的NULL InDate替换为该ProcessID的InDates的模式值。我已经计算了ProcessID的InDate模式，我无法弄清楚如何使用该值来替换带有ProcessID的EquipmentID的NULL值

以下是一个示例设置：

 CREATE TABLE dbo.Table_basic (
                InDate INT,
                EquipmentID INT,
                ProcessID nvarchar(50),
                SiteID INT
                )

INSERT INTO Table_basic (InDate, EquipmentID, ProcessID, SiteID)
VALUES (2001, 1,'1PAA',1),
        (2001,2,'1PAA',1),
        (NULL, 3,'1PAA',1),
        (2001,4,'1PAA',1),
        (1999, 5,'1PAA',1),
        (2001,6,'1PAB',1),
        (2001,7,'1PAC',1),
        (2001, 8,'2AA',2),
        (1999,9,'2AB',2),
        (NULL, 10,'2AB',2),
        (1999,11,'2AB',2),
        (1998,12,'2AB',2),
        (2001, 13,'2AB',2),
        (1999,14,'2AB',2),
        (2001, 15,'2AC',2),
        (2001,16,'2AC',2),
        (1986, 17,'3AA',3),
        (1985,18,'3AA',3),
        (1985,19,'3AA',3),
        (NULL, 20,'3AC',3),
        (2005,21,'3AC',3),
        (2005, 22,'3AC',3),
        (2005,23,'3AC',3);

这就是我在ProcessID中找到设备的InDate模式的方法。

WITH CTE_CountofEquipment AS
 (
  SELECT
    ProcessID
   ,SiteID
   ,cnt   = COUNT(1)
   ,rid   = ROW_NUMBER() OVER (PARTITION BY ProcessID ORDER BY COUNT(1) DESC)
   ,InDate
    FROM dbo.Table_basic 
  GROUP BY  SiteID, ProcessID, InDate
 )
 SELECT
   ProcessID
  ,cnt = cnt
  ,[SiteID]
  ,InDate
 FROM CTE_CountofEquipment
 WHERE rid = 1
 ORDER BY SiteID;

我想使用这些确定的模式来填充给定ProcessID的NULL InDate。

期望的结果示例：

(NULL, 3,'1PAA',1),
(2001, 3,'1PAA',1),
(2001, 3,'1PAA',1),
(1999, 3,'1PAA',1),
(2000, 3,'1PAA',1),
(2001, 3,'1PAA',1),

变为

(2001, 3,'1PAA',1), -- InDate updated to modal value
(2001, 3,'1PAA',1),
(2001, 3,'1PAA',1),
(1999, 3,'1PAA',1),
(2000, 3,'1PAA',1),
(2001, 3,'1PAA',1),

由于

Answer 1

我会像这样计算：

with modes as (
      select p.*
      from (select tb.processId, tb.indate, count(*) as cnt,
                   row_number() over (partition by tb.processId order by count(*) desc) as seqnum
            from table_basic tb
            group by tb.processId, tb.indate
           ) p
      where seqnum = 1
     )
update tb
    set indate = m.indate
    from table_basic tb join
         modes m
         on tb.processId = m.processId
    where indate is null;

这回答了您的问题。我不知道为什么你的模式计算使用SiteId。这不是问题的一部分。我不知道对NULL的{{1}}值的引用是什么。这也不是问题的一部分。

但是，您应该可以轻松地为模式或其他列的其他分组修改此内容。

Answer 2

您可以使用以下查询来执行UPDATE：

;WITH CTE_CountofEquipment AS (
    SELECT InDate, ProcessID, SiteID, 
           COUNT(*) OVER (PARTITION BY ProcessID, SiteID, InDate) AS cnt
    FROM dbo.Table_basic
), ToUpdate AS (
   SELECT InDate, ProcessID, SiteID,
          FIRST_VALUE(InDate) 
          OVER 
             (PARTITION BY ProcessID, SiteID
             ORDER BY cnt DESC ) AS mode
    FROM CTE_CountofEquipment
)
UPDATE ToUpdate
SET InDate = mode
WHERE InDate IS NULL

查询使用窗口函数来计算mode值：

COUNT OVER()用于确定每个InDate分区中每个ProcessID, SiteID切片的总数
FIRST_VALUE(InDate) is used to select the人口最多的InDate`

Demo here

使用动态值

2 个答案: