如何在 SQL 服務器中獲取最大值和對應日期

Question

我有一張位置、日期和海拔值的表格。 下面的查詢很簡單，但我試圖獲取與高度的最小/最大值相對應的最小/最大日期。

SELECT location, 
max(datetime) as max_date
COUNT(Altitude) as COUNT, 
AVG(Altitude) as AVG,
MIN(Altitude) as MIN,
max(Altitude) as MAX
FROM mydatabase
GROUP BY location

Answer 1

對於每個位置 select 最大和最小高度以及它們的最大最小日期時間。

    select location, Altitude, min([datetime]) dtmin, max([datetime]) dtmax
    from (
       SELECT location, Altitude, [datetime]
           , min(Altitude) over(partition by location) as aMIN
           , max(Altitude) over(partition by location) as aMAX
       FROM mydatabase
    ) t
    where Altitude in (aMIN, aMAX)
    group by location, Altitude
    order by location, Altitude;