TSQL - 來自單個查詢中的DOB的多個計數

Question

對不起，如果這是一個新手問題。是否有可能使用不同的條件在單個查詢中使用Count的列表。 基本上我試圖得到一個按年齡顯示申請人數量的清單。 例如 20 - 29 30 - 39 等

非常感謝， 安迪

Answer 1

;WITH AgeGroups AS (
SELECT 
    CASE 
    WHEN FLOOR(DATEDIFF(DAY, DOB, GETDATE())/365.25 BETWEEN 20 AND 29 
     THEN '20 - 29' 
    WHEN FLOOR(DATEDIFF(DAY, DOB, GETDATE())/365.25 BETWEEN 30 AND 39 
     THEN '30 - 39' 
    END AS AgeGroup 
FROM YourTable 
) 
SELECT 
    AgeGroup, 
    COUNT(*) AS AgeGroupCount 
FROM AgeGroups 
GROUP BY AgeGroup 

Answer 2

也許像這樣將工作

SELECT SUM(case where DATEDIFF(YEAR, [dob], GETDATE()) between 20 and 29 then 1 else 0) AS 'Age_20_29', 
SUM(case where DATEDIFF(YEAR, [dob], GETDATE()) between 30 and 39 then 1 else 0) AS 'Age_30_39', 
[etc.] 
FROM myTbl