Oracle NOT BETWEEN for string comparison does not give same result as <= and >= -

using oracle 11gr2 expression edition. data looks following

ordertype --------- zoco zosa zost 

we trying find out records column not between range of values.

if run query <= , >= operators: select * table ordertype <= 'zaaa' or ordertype >= 'zzzz'; 0 results. this right answer.

however, if use not between: select * table ordertype not between 'zaaa' , 'zzzz'; , gives multiple hits.

my understanding both syntax should give same result not. missing? reason want use not between because lot of our existing code has syntax , not want change without understanding reasons.

thank you.

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thanks posted. ran queries again , after fixing "or" in first query, results same. still have question of why oracle character sorting not recognizing expected, question difference between not between , <> false alarm. apologize confusion.

select * table ordertype <= 'zaaa' , ordertype >= 'zzzz'; 

no string can <= 'zaaa' and >= 'zzzz'. need use disjunction instead:

select * table ordertype < 'zaaa' or ordertype > 'zzzz'; 

^{btw, given between inclusive, not between exclusive}

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this common pitfall. have remember de morgan's laws:

not (a , b) same (not a) or (not b)

feel free experiment simple live example convince results quite coherent: http://sqlfiddle.com/#!4/d41d8/38326

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that being said, way (i can see) string zoco not being between zaaa , zzzz be:

• having hidden character behind z (i.e.: 'z'||chr(0)||'oco')
• or using locale such z-something considered different letter, collation order outside of given range. don't know if such locale exists, example, in welch, ll considered single letter should sorted after plain l. see http://en.wikipedia.org/wiki/alphabetical_order#language-specific_conventions
• or having homogplyphs such 0, 𐒠 or О instead of o in data.