Help with SQL statement

[DKenny]

Here's a 'One-pass' method
Note: I had to do this on SQLServer and I think you need a & rather than a + to concat string fields in Oracle.

SELECT	DEPT
	,SUM(AMOUNT)
FROM	DK_TEST
WHERE	CAST(CAST(MYYEAR AS CHAR(4))+ CAST([WEEK]  AS CHAR(2))AS INT) 
BETWEEN 200512 AND 200601
GROUP BY
	DEPT