Friday, 7 June 2013

Leap year function PLSQL

PL SQL Leap year function

Hi all, I didn't have time to write cause I had no time on my schedule :)
so I decided to refresh my blog with leap year calculator....

Some exceptions to this rule are required since the duration of a solar year is slightly less than 365.25 days. Over a period of four centuries, the accumulated error of adding a leap day every four years amounts to about three extra days. The Gregorian Calendar therefore omits 3 leap days every 400 years, omitting February 29 in the 3 century years (integer multiples of 100) that are not also integer multiples of 400.
For example, 1600 was a leap year, but 1700, 1800 and 1900 were not. Similarly, 2000 was a leap year, but 2100, 2200, and 2300 will not be. By this rule, the average number of days per year is 365 + 1/4 − 1/100 + 1/400 = 365.2425.

Why do we need Leap Years?

Leap Years are needed to keep our calendar in alignment with the Earth's revolutions around the sun. It takes the Earth approximately 365.242199 days – or 365 days, 5 hours, 48 minutes, and 46 seconds (a tropical year) – to circle once around the Sun.

However, the Gregorian calendar has only 365 days in a year, so if we didn't add a day on February 29 nearly every 4 years, we would lose almost six hours off our calendar every year. After only 100 years, our calendar would be off by approximately 24 days!
The year is evenly divisible by 4;
If the year can be evenly divided by 100, it is NOT a leap year, unless;
The year is also evenly divisible by 400. Then it is a leap year.

Years are Leap Years?

In the Gregorian calendar 3 criteria must be taken into account to identify leap years:

This means that 2000 and 2400 are leap years, while 1800,1900,2100,2200,2300 and 2500 are NOT leap years.

The year 2000 was somewhat special as it was the first instance when the third criterion was used in most parts of the world since the transition from the Julian to the Gregorian Calendar

Why should I care about Leap Years?

The 29th day added to February  (leap day ) brings a smidgen of a financial boost for some consumers and slight adjustments for businesses that rely on daily sales and workers who are paid by the hour.
So if February is leaping then you must add +1 day to the monthly salary if you are accountant or to calculate extra profit for February....

Little function for leaping year

 -- function returns 1 for leaping year
v_remainder1 number(5,2);
v_remainder2 number(5,2);
v_remainder3 number(5,2);
o_value pls_integer;
   v_remainder1 := mod(i_year,4);
   v_remainder2 := mod(i_year,100);
   v_remainder3 := mod(i_year,400);
   if ((v_remainder1 = 0 and v_remainder2 <> 0 ) or v_remainder3 = 0) then
      o_value := 1;
      return o_value;  
      o_value := 0;
      return o_value;  
   end if;
end f_leap_year;


  1. Bok Vedrane,
    simple one ;)

    select decode(to_char(to_date('DEC 31, &year','MON DD, YYYY'),'DDD'),'365','NOT leap','it is leap year') from dual;