case语句在SQL Server中创建X场和where子句X字段2008

Question

表数据和结构：

Name  DateOfBirth 
Thuso  1987-02-27 00:00:00.000 
Sue  1968-02-27 00:00:00.000 
Zee  1999-02-27 00:00:00.000

查询：

USE [PersonDatabase] 
GO 

DECLARE @AGE int =1 
Select Name, X=CASE 
    WHEN((year(getdate()) - year(DateOfBirth)) >=0 AND (year(getdate()) - year(DateOfBirth)) <=17) THEN 1 
    WHEN((year(getdate()) - year(DateOfBirth)) >= 18 AND (year(getdate()) - year(DateOfBirth)) <=29) THEN 2 
    WHEN((year(getdate()) - year(DateOfBirth)) >= 30 AND (year(getdate()) - year(DateOfBirth)) <=60) THEN 3 
END 
froM PersonDatabase.mem.Namebirth 
WHERE (X=@AGE) 

它产生的输出我没有想到的问题：

X 
1 
2 
3 

我的问题是：我在哪里出错我的WHERE条款的查询，为它产生的输出为：

X 
1 

Answer 1

我看到固定查询的方式有两种：

DECLARE @AGE int =1 
Select Name, CASE 
    WHEN((year(getdate()) - year(DateOfBirth)) >=0 AND (year(getdate()) - year(DateOfBirth)) <=17) THEN 1 
    WHEN((year(getdate()) - year(DateOfBirth)) >= 18 AND (year(getdate()) - year(DateOfBirth)) <=29) THEN 2 
    WHEN((year(getdate()) - year(DateOfBirth)) >= 30 AND (year(getdate()) - year(DateOfBirth)) <=60) THEN 3 
END 
froM PersonDatabase.mem.Namebirth 
WHERE 
CASE 
     WHEN((year(getdate()) - year(DateOfBirth)) >=0 AND (year(getdate()) - year(DateOfBirth)) <=17) THEN 1 
     WHEN((year(getdate()) - year(DateOfBirth)) >= 18 AND (year(getdate()) - year(DateOfBirth)) <=29) THEN 2 
     WHEN((year(getdate()) - year(DateOfBirth)) >= 30 AND (year(getdate()) - year(DateOfBirth)) <=60) THEN 3 
    END = @AGE 

OR

SELECT Name, X FROM(
    Select Name, X=CASE 
    WHEN((year(getdate()) - year(DateOfBirth)) >=0 AND (year(getdate()) - year(DateOfBirth)) <=17) THEN 1 
    WHEN((year(getdate()) - year(DateOfBirth)) >= 18 AND (year(getdate()) - year(DateOfBirth)) <=29) THEN 2 
    WHEN((year(getdate()) - year(DateOfBirth)) >= 30 AND (year(getdate()) - year(DateOfBirth)) <=60) THEN 3 
    END 
    froM PersonDatabase.mem.Namebirth 
) T 
WHERE (T.X=@AGE)