平均在SQL Server 2000

Question

對於偶數行式爲中位數是（104.5 + 108）/ 2對於下表和對於奇數行是108，用於表以下的

Total  Total 

100   100 
101   101 
104.5  104.5 
108   108 
108.3  108.3 
112   112 
      114 

代碼在SQL Server工作2008但不在SQL Server 2000中，因爲它不理解row_number()和over。

我們應該如何更改較低的代碼才能使其在SQL Server 2000上運行？

select avg(Total) median from 
(select Total, 
rnasc = row_number() over(order by Total), 
rndesc = row_number() over(order by Total desc) 
from [Table] 
) b 
where rnasc between rndesc - 1 and rndesc + 1 

Answer 1

SELECT Median = AVG(Total) FROM 
( 
    SELECT Total FROM ( 
     SELECT TOP 1 Total = Total * 1.0 FROM 
     ( 
      SELECT TOP 50 PERCENT Total 
      FROM dbo.[Table] ORDER BY Total 
     ) AS sub_a 
     ORDER BY 1 DESC 
    ) AS sub_1 
    UNION ALL 
    SELECT Total FROM ( 
     SELECT TOP 1 Total = Total * 1.0 FROM 
     ( 
      SELECT TOP 50 PERCENT Total 
      FROM dbo.[Table] ORDER BY Total DESC 
     ) AS sub_b 
     ORDER BY 1 
    ) AS sub_2 
) AS median; 

Answer 2

如果你只想要一箇中位數，你可以使用這個簡單的查詢。

SELECT 
(
    (SELECT MAX(Total) FROM 
    (SELECT TOP 50 PERCENT Total FROM [Table] ORDER BY Total) AS BottomHalf) 
    + 
    (SELECT MIN(Total) FROM 
    (SELECT TOP 50 PERCENT Total FROM [Table] ORDER BY Total DESC) AS TopHalf) 
)/2.0 AS Median 

來源：Function to Calculate Median in Sql Server