happy new year 2013!

the year has changed and there has been a problem in a query.

I can't not retrieve the data for the month of December 2012, the output of alias contacttotals_previous_month is null.

the problem is this case in the query:
Code:
	SUM(
		CASE
		WHEN MONTH (visitdate) = MONTH (
			CURRENT_DATE () - INTERVAL 1 MONTH
		)
		AND YEAR (visitdate) = YEAR (CURRENT_DATE()) THEN
			visitorcount
		END
	) AS contacttotals_previous_month,
In the case January current year versus December previous year which solution can be find?
thank you
Code:
mysql> SELECT
	SUM(
		CASE
		WHEN visitorcount THEN
			visitorcount
		END
	) AS contacttotals,
	SUM(
		CASE
		WHEN MONTH (visitdate) = MONTH (CURRENT_DATE())
		AND YEAR (visitdate) = YEAR (CURRENT_DATE()) THEN
			visitorcount
		END
	) AS contacttotals_current_month,
	SUM(
		CASE
		WHEN MONTH (visitdate) = MONTH (
			CURRENT_DATE () - INTERVAL 1 MONTH
		)
		AND YEAR (visitdate) = YEAR (CURRENT_DATE()) THEN
			visitorcount
		END
	) AS contacttotals_previous_month,
	SUM(
		CASE
		WHEN visitdate = CURRENT_DATE () THEN
			visitorcount
		END
	) AS contacttotals_today,
	SUM(
		CASE
		WHEN visitdate = CURRENT_DATE () - INTERVAL 1 DAY THEN
			visitorcount
		END
	) AS contacttotals_yest
FROM
	tbl_session;

+---------------+-----------------------------+-------------------------------+--------------------+--------------------+
| contacttotals | contacttotals_current_month | contacttotals_previous_month  | contacttotalsToday | contacttotals_yest |
+---------------+-----------------------------+-------------------------------+--------------------+--------------------+
| 8319824       | 1581                        | NULL                          | 1581               | 4433               |
+---------------+-----------------------------+-------------------------------+--------------------+--------------------+

1 row in set