TSQL - 来自单个查询中的DOB的多个计数

Question

对不起，如果这是一个新手问题。是否有可能使用不同的条件在单个查询中使用Count的列表。 基本上我试图得到一个按年龄显示申请人数量的清单。 例如 20 - 29 30 - 39 等

非常感谢， 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

也许像这样将工作

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