Check for leap year

Question

How do I check if a year is a leap year?

I have this code:

declare @year int
set @year = 1968

SELECT CASE WHEN @YEAR = <LEAPYEAR> THEN 'LEAP YEAR' ELSE 'NORMAL YEAR' END

Expected result:

LEAP YEAR

Answer 1

Check for 29th Feb:

CASE WHEN ISDATE(CAST(@YEAR AS char(4)) + '0229') = 1 THEN 'LEAP YEAR' ELSE 'NORMAL YEAR' END

or use the following rule

CASE WHEN (@YEAR % 4 = 0 AND @YEAR % 100 <> 0) OR @YEAR % 400 = 0 THEN 'LEAP YEAR'...

Answer 2

MOST EFFICIENT LEAP YEAR TEST:

CASE WHEN @YEAR & 3 = 0 AND (@YEAR % 25 <> 0 OR @YEAR & 15 = 0) THEN ...

Adapted from: http://stackoverflow.com/a/11595914/3466415