Current Year To Date, Last Year To Date, and Other - sql

Question

I need to classify a set of dates as either 'Cur. YTD', 'Lst. YTD', or 'Other'. YTD is based upon getdate(). I have a temp table for testing that has a single column called 'calendar_date' of type DATETIME. I came up with this logic and it appears to work. I'm just wondering if this approach makes good sense from a performance perspective or if something else might be better.
select calendar_date,
case when (MONTH(calendar_date) < MONTH(getdate()))
or (MONTH(calendar_date) = MONTH (getdate())
AND DAY(calendar_date) <= DAY(getdate())) then
case when YEAR(calendar_date) = YEAR(GETDATE()) then 'CYTD'
when YEAR(calendar_date) = YEAR(getdate()) - 1 then 'LYTD'
else 'Other'
end
else 'Other'
end as Tim_Tag_YTD
from #temp1

Answer 1

Your logic looks good and will work as-is.
An alternative which simplifies a little, which assumes you have no future data.
select
calendar_date,
Tim_Tag_YTD = case DATEDIFF(YEAR, calendar_date, GETDATE())
when 0 then 'CYTD'
when 1 then 'LYTD'
else 'Other'
end
from #temp1;
In the case of your logic, you are explicitly putting future data into 'Other', which you can also do like this:
select
calendar_date,
Tim_Tag_YTD = case when calendar_date > GETDATE() then 'Other' else
case DATEDIFF(YEAR, calendar_date, GETDATE())
when 0 then 'CYTD'
when 1 then 'LYTD'
else 'Other'
end
end
from #temp1;

Answer 2

Sometimes something unintuitive performs faster. Something like this might be worth a shot.
set variable #FirstOfLastYear to Jan 1 of last year
using sql server date functions
set #FirstOfThisYear = DateAdd(year, 1, #FirstOfLastYear)
select 'last year' period
, whatever else you need
from #temp1 where calendar_date >= #FirstOfLastYear
and calendar_date < #FirstOfThisYear
union
select 'this year' period
, whatever else you need
from #temp1 where calendar_date >= #FirstOfThisYear
and calendar_date < getDate ()
union
select 'other' period
, whatever else you need
from #temp1 where calendar_date <= #FirstOfLastYear
or calendar_date > getdate()
You'll never know unless you try.