SELECT Months.m AS month, COUNT(Tests.receiveDate) AS total FROM
(
SELECT 1 as m
UNION SELECT 2 as m
UNION SELECT 3 as m
UNION SELECT 4 as m
UNION SELECT 5 as m
UNION SELECT 6 as m
UNION SELECT 7 as m
UNION SELECT 8 as m
UNION SELECT 9 as m
UNION SELECT 10 as m
UNION SELECT 11 as m
UNION SELECT 12 as m
) as Months
LEFT JOIN Tests on Months.m = MONTH(Tests.receiveDate)
GROUP BY
Months.m
年を特定したい場合は、これを試してください。
SELECT Months.m AS month, COUNT(Tests.receiveDate) AS total FROM
(
SELECT 1 as m
UNION SELECT 2 as m
UNION SELECT 3 as m
UNION SELECT 4 as m
UNION SELECT 5 as m
UNION SELECT 6 as m
UNION SELECT 7 as m
UNION SELECT 8 as m
UNION SELECT 9 as m
UNION SELECT 10 as m
UNION SELECT 11 as m
UNION SELECT 12 as m
) as Months
LEFT JOIN Tests on Months.m = MONTH(Tests.receiveDate)
AND YEAR(Tests.receiveDate) = '2012'
GROUP BY Months.m