특정 달에 대한 데이터가 없는 경우에도 MySQL에서 월별 레코드를 검색하는 방법은 무엇입니까?

SELECT COUNT(`userID`) AS total, DATE_FORMAT(`userRegistredDate`, '%b') AS MONTH, YEAR(`userRegistredDate`) AS year
FROM `users`
GROUP BY DATE_FORMAT(FROM_UNIXTIME(`userRegistredDate`, '%b'))

SELECT COUNT(u.userID) AS total, m.month
FROM (
SELECT 'Jan' AS MONTH
UNION SELECT 'Feb' AS MONTH
UNION SELECT 'Mar' AS MONTH
UNION SELECT 'Apr' AS MONTH
UNION SELECT 'May' AS MONTH
UNION SELECT 'Jun' AS MONTH
UNION SELECT 'Jul' AS MONTH
UNION SELECT 'Aug' AS MONTH
UNION SELECT 'Sep' AS MONTH
UNION SELECT 'Oct' AS MONTH
UNION SELECT 'Nov' AS MONTH
UNION SELECT 'Dec' AS MONTH
) AS m
LEFT JOIN users u
ON MONTH(STR_TO_DATE(CONCAT(m.month, ' 2013'),'%M %Y')) = MONTH(u.userRegistredDate)
AND YEAR(u.userRegistredDate) = '2013'
GROUP BY m.month
ORDER BY 1+1;

SELECT COUNT(u.userID) AS total, DATE_FORMAT(merge_date,'%b') AS month, YEAR(m.merge_date) AS year
FROM (
SELECT '2013-01-01' AS merge_date
UNION SELECT '2013-02-01' AS merge_date
UNION SELECT '2013-03-01' AS merge_date
UNION SELECT '2013-04-01' AS merge_date
UNION SELECT '2013-05-01' AS merge_date
UNION SELECT '2013-06-01' AS merge_date
UNION SELECT '2013-07-01' AS merge_date
UNION SELECT '2013-08-01' AS merge_date
UNION SELECT '2013-09-01' AS merge_date
UNION SELECT '2013-10-01' AS merge_date
UNION SELECT '2013-11-01' AS merge_date
UNION SELECT '2013-12-01' AS merge_date
) AS m
LEFT JOIN users u
ON MONTH(m.merge_date) = MONTH(u.userRegistredDate)
AND YEAR(m.merge_date) = YEAR(u.userRegistredDate)
GROUP BY m.merge_date
ORDER BY 1+1;