oracle 创建一个 pl/sql 函数并找到闰年
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Create a pl/sql function & find leap years
提问by Aditya
Please let me know how to find a leap year through PL/SQL function. Suppose we input any number, how can we find out it is leap year or not?
请让我知道如何通过 PL/SQL 函数找到闰年。假设我们输入任何数字，我们如何知道它是不是闰年？
回答by Dba
Try the below function,
试试下面的功能，
FUNCTION leap_year_or_not(
i_year IN NUMBER)
RETURN VARCHAR2
IS
l_var VARCHAR2(20);
BEGIN
IF TO_CHAR(LAST_DAY(TO_DATE('01/02/'||i_year, 'dd/mm/yyyy')), 'DD') = 29 THEN
l_var := 'Leap Year';
ELSE
l_var := 'Not Leap Year';
END IF;
RETURN l_var;
END;
回答by Nick Krasnov
Basically, if a year is divisible by 4 without a remainder and not by 100 it's a leap year. But, if the year is divisible by both 4 and 100 without a remainder, it also should be divisible by 400 to be a leap year.
基本上，如果一年可以被 4 整除而没有余数而不是 100，那么它就是闰年。但是，如果年份可以被 4 和 100 整除而没有余数，那么它也应该被 400 整除才能成为闰年。
So a function, which will tell you whether a year you've provided is a leap one or not could look like this:
所以一个函数，它会告诉你你提供的一年是否是一个闰年，它看起来像这样：
create or replace package utl is
function is_leap_year(p_year in number) return number;
end;
/
Package created
create or replace package body utl is
function is_leap_year(p_year in number) return number is
begin
return case
when ( mod(p_year, 4) = 0 and mod(p_year, 100) <> 0 ) or
( mod(p_year, 400) = 0 ) then 1
else 0
end;
end;
end;
/
Package body created
Test case:
测试用例：
SQL> select 1999 + level as test_year
2 , utl.is_leap_year(1999 + level) as is_leap
3 from dual
4 connect by level <= 12
5 ;
Result:
结果：
TEST_YEAR IS_LEAP
---------- ----------
2000 1
2001 0
2002 0
2003 0
2004 1
2005 0
2006 0
2007 0
2008 1
2009 0
2010 0
2011 0
12 rows selected
