Date between dates, ignore year

Since you indicated that you're fine storing an arbitrary year in your data, then you can keep using a DATE type. Then it just comes down to how to query.

• Store the fields using a fixed arbitrary year. You should use a leap-year to accommodate the possibility of Feb 29th values. Year 2000 works nicely. (0004 won't work because it's too small for MySQL's Date type.)

• Replace the year of any value you're querying with the same year.

• Consider ranges that cross over the end of one year and into the next. To fully answer that, you'll need a query such as the following:

  SET @dt = cast(CONCAT('2000',RIGHT(thesourcedatevalue,6)) as DATE);
  
  SELECT some_column FROM dates
  WHERE (since <= upto AND since <= @dt AND upto >= @dt) OR
        (since > upto AND (since <= @dt OR upto >= @dt))
  

  Here is a SQL Fiddle that demonstrates

• For performance, you should be sure that there is an index that includes the since and upto fields.

SELECT foo FROM dates WHERE DATE_FORMAT('2014-01-15', "%m-%d") 
    BETWEEN DATE_FORMAT(`since`,"%m-%d") AND DATE_FORMAT(`upto`,"%m-%d")

Here's the SQL FIDDLE demo

Use the DayOfYear function:

 SELECT foo FROM dates WHERE DayOfYear('2014-05-05') 
    BETWEEN DayOfYear(`since`) AND DayOfYear(`upto`)