SELECT DATEDIFF(
 (SELECT DATE(date_field) FROM table WHERE id = '1' AND status_id = '2' ORDER BY date_field DESC LIMIT 1),
 (SELECT DATE(date_field) FROM table WHERE id = '1' AND status_id = '1' ORDER BY date_field DESC LIMIT 1)
	) AS difference

I use something similar to the example to get the difference between statuses in a status log table that I have. It comes in handy when determining the number of days between status changes. This works in MySQL 5.0.

calculate the difference between dates in one columns within the same  table

mysql, date

MySQL