Sort upcoming birthdays based on current date

Question

I have the following table of people and their birthdays:

name        birthday
----------------------
yannis      1979-06-29
natalia     1980-08-19
kostas            


        

Answer 1

Here is one way:

• Calculate current year - year of birth
• Add the resulting number of years to the date of birth
• You now have the birthday this year, if this date has passed then add one more year
• Sort the results by that date

SELECT
    name,
    birthday,
    birthday + INTERVAL (YEAR(CURRENT_DATE) - YEAR(birthday))     YEAR AS currbirthday,
    birthday + INTERVAL (YEAR(CURRENT_DATE) - YEAR(birthday)) + 1 YEAR AS nextbirthday
FROM birthdays
ORDER BY CASE
    WHEN currbirthday >= CURRENT_DATE THEN currbirthday
    ELSE nextbirthday
END

Notes:

• Today's birthdays appears first regardless of current time
• February 29 birthday is treated equal to February 28 birthday for common years e.g.
  • On Jan/1/2019 both Feb 28 and Feb 29 birthdays (2019) are sorted equal
  • On Mar/1/2019 Feb 28 and Feb 29 birthdays (2020) are sorted as expected

SQLFiddle