Set default value if no result found - mysql

Question

I have the following query
SELECT count(*) as count, Month(created_at) as month
FROM products
WHERE marketplace_id=21
and status='counterfeit'
and created_at < Now()
and created_at > DATE_ADD(Now(), INTERVAL - 5 MONTH)
group by month(created_at)
it return result as
+-------+-------+
| count | month |
+-------+-------+
| 410 | 1 |
| 174 | 2 |
| 301 | 3 |
| 329 | 4 |
| 141 | 12 |
+-------+-------+
in case a month does not have values it doesn't returns it at all, but I want the default value 0 to be set for that month.
I have tried this link Return a default value if no rows found
and
Returning a value if no result
I am not sure whether I am not able to implement it correctly or this is not what I want

Answer 1

Try this, seems to be a little stupid, but may help for you;)
SELECT SUM(count) AS count, month
FROM (
SELECT count(*) as count, Month(created_at) as month FROM products WHERE marketplace_id=21
and status='counterfeit' and created_at < Now() and created_at > DATE_ADD(Now(), INTERVAL - 5 MONTH)
group by month(created_at)
UNION
SELECT * FROM (
SELECT 0 AS count, 1 AS month
UNION SELECT 0 AS count, 2 AS month
UNION SELECT 0 AS count, 3 AS month
UNION SELECT 0 AS count, 4 AS month
UNION SELECT 0 AS count, 5 AS month
UNION SELECT 0 AS count, 6 AS month
UNION SELECT 0 AS count, 7 AS month
UNION SELECT 0 AS count, 8 AS month
UNION SELECT 0 AS count, 9 AS month
UNION SELECT 0 AS count, 10 AS month
UNION SELECT 0 AS count, 11 AS month
UNION SELECT 0 AS count, 12 AS month) M
WHERE M.month < Month(Now()) AND M.month > Month(DATE_ADD(Now(), INTERVAL - 5 MONTH)))
) tmp
GROUP BY mouth
ORDER BY month

Answer 2

You could create another table with default values
test_defaults
-----------------
| month | count |
and than just left join it with your table of values so if the value is found within the main table, it will be used, if not value from test_defaults would be used (we will use COALESCE function which returns first non null value):
SELECT t1.month, COALESCE(t2.count, t1.count)
FROM test_defaults t1
LEFT JOIN test_data t2 ON t1.month = t2.month
ORDER BY t1.month;
Here's a working SqlFiddle demo