sql server – Select statement is running but won’t print/ignores conditions

I am writing a select statement to get the average cost of an item for the last year. I’m working with two statements. The first is ignoring the date and out-putting an average for a random year. the second is running but isn’t printing anything out. I only need one to work. Any ideas?

Also, the date for the file is set up like yy/mm/dd and for the current century it is 1yy/mm/dd and I cannot change it.

1st Statement: (the one ignoring the date)

SELECT SUBSTRING(DATE, 1, 3), AVG(AMOUNT/QUANTITY) FROM FILE1
WHERE ITEM = IFITEM  GROUP BY SUBSTRING(DATE, 1, 3)           
HAVING SUBSTRING(DATE, 1, 3) > (SUBSTRING(MAX(DATE), 1, 3) - 1)

2nd Statement: (the one not printing)

SELECT SUBSTRING(DATE, 1, 3), AVG(AMOUNT/QUANTITY) FROM FILE1
WHERE SUBSTRING(DATE, 1, 3) > (SELECT (SUBSTRING(MAX(DATE), 1, 3) - 1) 
FROM FILE1 WHERE ITEM = IFITEM )