Note: I’ve edited this to fix what I believe was a significant bug. The currently posted version works for me.
This should work after you modify the field and table names to correspond to your database.
SELECT
BRTHDATE AS BIRTHDAY
,FLOOR(DATEDIFF(dd,EMP.BRTHDATE,GETDATE()) / 365.25) AS AGE_NOW
,FLOOR(DATEDIFF(dd,EMP.BRTHDATE,GETDATE()+7) / 365.25) AS AGE_ONE_WEEK_FROM_NOW
FROM
"Database name".dbo.EMPLOYEES EMP
WHERE 1 = (FLOOR(DATEDIFF(dd,EMP.BRTHDATE,GETDATE()+7) / 365.25))
-
(FLOOR(DATEDIFF(dd,EMP.BRTHDATE,GETDATE()) / 365.25))
Basically, it gets the # of days from their birthday to now, and divides that by 365 (to avoid rounding issues that come up when you convert directly to years).
Then it gets the # of days from their birthday to a week from now, and divides that by 365 to get their age a week from now.
If their birthday is within a week, then the difference between those two values will be 1. So it returns all of those records.