Question

I have Table with columns: “Month” and “Year”, and other data.

All row in Table have different values “Month” and “Year”.

But for some Month and Year rows don’t exist.

I want create SQL-query (… where year in (2010, 2011, 2012) …), that in result this SQL-query have all Month for select Year and if some month don’t exist else add it to result with 0 in other data columns.

Example:
Input: Table

data / month / year
+-----+---+------+
| 3.0 | 1 | 2011 |
| 4.3 | 3 | 2011 |
| 5.7 | 4 | 2011 |
| 2.2 | 5 | 2011 |
| 5.4 | 7 | 2011 |
+-----+---+------+

Output: SELECT … WHERE year IN (2011)

+-----+----+------+
| 3.0 |  1 | 2011 |
|   0 |  2 | 2011 |
| 4.3 |  3 | 2011 |
| 5.7 |  4 | 2011 |
| 2.2 |  5 | 2011 |
|   0 |  6 | 2011 |
| 5.4 |  7 | 2011 |
|   0 |  8 | 2011 |
|   0 |  9 | 2011 |
|   0 | 10 | 2011 |
|   0 | 11 | 2011 |
|   0 | 12 | 2011 |
+-----+----+------+

Answer 1

Try Partition Outer Join:

SELECT
  NVL(T.DATA, 0) DATA,
  F.MONTH,
  T.YEAR
FROM <your_table> T
PARTITION BY(T.YEAR)
RIGHT JOIN (SELECT LEVEL MONTH FROM DUAL CONNECT BY LEVEL <= 12) F ON T.MONTH = F.MONTH

Add your WHERE clause at the end or create a view with that definition and query against it.