Get the correct days in vacation accumulation report - sql

Question

I need acculate how many days between today and Employee hiredate(but do not care the year). That mearn if one employee hire in 07/1/2012, i want to get a result is today 07/15/2013-07/1/2013, that is 15 days. I do not need the hire year 2012.
i play around with the dateadd and datediff but just did not get the correct result.
SELECT
Co Employee,
LastName,
FirstName,
dateadd(dd, DATEDIFF(dd,CURRENT_TIMESTAMP,0),HireDate)
FROM dbo.PREH

Answer 1

You could use modulus division:
SELECT DATEDIFF(DAY,'20120101',GETDATE())%365
The downside is that you're treating leap year the same as every other year, which you could handle with case logic.
In your code:
SELECT
Co Employee,
LastName,
FirstName,
DATEDIFF(DAY,HireDate,GETDATE())%365 AS DaysThisYear
FROM dbo.PREH

Answer 2

This is a bit brute force, perhaps, but it seems to work. The idea is to add a number of years to the hiredate, then to check that against the current date. When it is greater, use one fewer years:
select (case when DATEADD(year, datediff(year, hiredate, getdate()), hiredate) < GETDATE()
then DATEDIFF(dd, DATEADD(year, datediff(year, hiredate, getdate()), hiredate), getdate())
else DATEDIFF(dd, DATEADD(year, datediff(year, hiredate, getdate()) - 1, hiredate), getdate())
end)
from preh;
The problem is that datediff() with year returns the number of times that the year boundary is crossed, not the number of years between two dates as a span. So, there is one year between 2012-12-30 and 2013-01-01, and there is one year between 2012-01-01 and 2013-12-31.

Answer 3

It sounds like you're dropping the year just as part of formatting the output. Formatting shouldn't affect the underlying data though. The last element of your tuple should be:
datediff(day, HireDate, getdate())
That way you can do arithmetic on the data, and save the formatting for downstream, when it's needed.