Between clause is not working for me

Question

my query does not give me the right output. when I use 1-12-2008 for min value and 11-12-2008 for max value. I was supposed to get result only for year 2008 but i am getting the result that includes year 2000,2001.....any idea why i am not getting the right result?
thanks
SELECT   v.vendor "Vendor Id", r.addrnum, v.vnamel "Vendor Name", r.aaddr1,
         r.acity, r.vasst1, r.astate state, r.azipcode,
         TO_CHAR (MAX (p.datepur), 'MM/DD/YYYY') "Last Plan Purchased Date",
         TO_CHAR (MAX (p.datepur), 'YYYY/MM/DD') "Plan Purchased Date",
         TRIM (r.aaddr1 || DECODE (TRIM (r.aaddr2), NULL, '', ' - ')
               || r.aaddr2
              ) address,
         SUBSTR (DECODE (TRIM (r.vasst1),
                         NULL, 'N/A',
                         '000/000-0000?', 'N/A',
                         '000/000-0000', 'N/A',
                         r.vasst1
                 1,
                 12
                ) fax,
         SUBSTR (DECODE (TRIM (r.aphone),
                         NULL, 'N/A',
                         '000/000-0000?', 'N/A',
                         r.aphone
                 1,
                 12
                ) phone
    FROM vendor v, vendaddr r, planhold p
   WHERE v.vendor = r.vendor
     AND p.vendor = r.vendor
   --  AND (p.datepur >= TO_DATE ('01-01-2000', 'MM-DD-YYYY'))
     AND p.datepur IN (SELECT MAX (p.datepur)
                         FROM planhold p
                        WHERE p.vendor = r.vendor)
     AND v.vobsolet = 'N'
     AND v.vnamel LIKE '%'
     AND r.astate LIKE '%'
--minvalue and max value test
     AND (TO_CHAR (p.datepur, 'MM-DD-YYYY') BETWEEN '&MINVALUE' AND '&MAXVALUE')
GROUP BY v.vendor,
         r.addrnum,
         v.vnamel,
         r.aaddr1,
         r.aaddr2,
         r.acity,
         r.astate,
         r.azipcode,
         r.aphone,
         r.vasst1,
         p.datepur

Answer 1

You are comparing dates as strings. You need to compare dates as dates.
AND (TO_CHAR (p.datepur, 'MM-DD-YYYY') BETWEEN '&MINVALUE' AND '&MAXVALUE')
Should be:
AND (p.datepur BETWEEN to_date('&MINVALUE', 'MM-DD-YYYY') AND to_date('&MAXVALUE', 'MM-DD-YYYY'))
If you compare them as strings, then:
'10-20-2001'
is between '10-10-2008' and '10-30-2009', alphabetically.