Problem with 'order by' and comparison operator with varchar2 field

Question

I have a problem with the following sql query (field1 is varchar2):
SELECT field1
FROM tablename
WHERE field1 > 'AA10BB'
ORDER BY field1
The contents of field1 is:
AA10BB
AA10-10BB
AA10-12BB
The sql query without the WHERE clause sorts field1 this way:
AA10BB
AA10-10BB
AA10-12BB
But the sql query with the WHERE clause has no hits.
It seems that when sorting the minus character is greater than the 'B' character and
at the comparison ( > 'AA10BB' ) the minus character is lower than the 'B' character!
The database and client NLS_PARAMTER are GERMAN_GERMANY.
The database is 9.2.0.7
Has anyone an idea?

Answer 1

thanks for your fast reply!
My problem was that NLS_SORT was set to 'GERMAN' and NLS_COMP to 'BINARY'.
NLS_SORT = GERMAN orders the varchar2 fields in form of 'a A b B ... 0 1 2 3 ..'
NLS_COMP = BINARY compares binary (ASCII-Table).
I use now:
SELECT field1
FROM tablename
WHERE field1 > 'AA10BB'
ORDER BY NLSSORT(field1, 'NLS_SORT = Binary'');