Question

我想按日期对数据进行分组，然后找到＆＃34; Value＆＃34;对于MAX（＆＃34; SeqNumber＆＃34;）。如何在聚合查询中执行此操作。

我尝试了以下内容，但它给出了错误。

专栏＆＃39; MyTable.SeqNumber＆＃39;在选择列表中无效，因为它是不包含在聚合函数或GROUP BY子句中。 Msg 8120，Level 16，State 1，Line 22 Column＆＃39; MyTable.Value＆＃39;是无效的在选择列表中，因为它不包含在聚合中函数或GROUP BY子句。

Columns:

Date: date
Time: time
Value: float
Code: varchar  <<Added in EDIT
SeqNumber: int

编辑查询：

SELECT MAX(case [Code] when 'GOLD' then [Value] end) AS BestGold, 
       MAX(case [Code] when 'SILVER' then [Value] end) as BestSilver
       (CASE WHEN [SeqNumber]=MAX([SeqNumber]) THEN [Value] END) AS HIGHEST << Problem
FROM [MyTable]
GROUP BY [Date]

Answer 1

WITH CTE AS (
    SELECT *,
           ROW_NUMBER() OVER (PARTITION BY [Date] ORDER BY Sequence DESC) AS RN
    FROM YourTable)
SELECT [Value] AS Highest
FROM CTE
WHERE RN = 1;

Answer 2

您可以使用group by和sub query -

来实现此目的

select t1.* 
from [MyTable] t1 join 
( SELECT 
  MAX([SeqNumber]) as MX_SeqNumber  -- you can add your additional columns here 
  FROM [MyTable]
  GROUP BY [Date] ) as t2
on t1.[SeqNumber] = t2.MX_SeqNumber

如何从GROUP BY

2 个答案: