MySQL: get MAX or GREATEST of several columns, but with NULL fields

Question

I\'m trying to select the max date in three different fields in each record (MySQL) So, in each row, I have date1, date2 and date3: date1 is always filled, date2 and date3 c

Answer 1

Use COALESCE

SELECT id, 
   GREATEST(date1, 
     COALESCE(date2, 0),
     COALESCE(date3, 0)) as datemax 
FROM mytable

Update: This answer previously used IFNULL which does work, but as Mike Chamberlain pointed out in the comments, COALESCE is actually the preferred method.