MySQL 中 select 闰年的查询条件

Question

I have a year column in one of my table and i need to find those years which are leap year in MySQL. The table name is 'Movie' and I have a particular year and title column in it. How to find the movies in leap year in SQL query?

I wrote the above query but got the year 'I 2009' in my answer.

SELECT year, title from Movie where year%4=0 AND (year%100!=0 OR year%400=0)

The head of the data is like this:

    title                       Year
0   The Avengers                2012
1   Captain America: Civil War  2016
2   Lion                        2016
3   Slumdog Millionaire         2008
4   2012                      I 2009

Answer 1

SELECT @year,
       DAY(CONCAT(@year, '-03-01') - INTERVAL 1 DAY) = 29 AS is_leap;

or

SELECT @year,
       !MOD(@year, 4) - !MOD(@year, 100) + !MOD(@year, 400) AS is_leap;

---

Accordingly

SELECT year, title 
FROM Movie 
WHERE DAY(CONCAT(year, '-03-01') - INTERVAL 1 DAY) = 29

or

SELECT year, title 
FROM Movie 
WHERE !MOD(year, 4) - !MOD(year, 100) + !MOD(year, 400)

Answer 2

For all years when there are movies, this suffices:

where year % 4 = 0 

The more exact expression is:

where (year % 4 = 0 and year % 100 <> 0) or
      (year % 400 = 0)

IN is not appropriate for this condition.

Answer 3

Is the data type of the year column a character type? By using ceil and cast functions, it checks whether it is in numerical format.

SELECT year, title from Movie where year%4=0 AND (year%100!=0 OR year%400=0) AND year=cast(ceil(year) as char);

4 2012 I 2009

It may be an application problem. If the data of "2012" that matched the conditions of the leap year is in the year column, and the data of the title column is NULL, so the title column is misaligned and the year column output like it. If above, I think that 'I ' is incorrect data output by referring to the area outside the range.

Answer 4

Need to format the Year column and then check the Leap Year condition.

WHERE (
(
   CAST(SUBSTR(TRIM(year),-4) AS INTEGER)%4=0 
   AND 
   CAST(SUBSTR(TRIM(year),-4) AS INTEGER)%100!=0
)

OR 
(
 CAST(SUBSTR(TRIM(year),-4) AS INTEGER)%100=0 
 AND 
 CAST(SUBSTR(TRIM(year),-4) AS INTEGER)%400=0)
)