An SQL statement like:

select * from (
  select '000000000000' as x from dual
  union
  select '978123456789' as x from dual
  union 
  select 'B002AACD0A' as x from dual
) /*where x>'000000000000'*/ order by x;

Yields:

B002AACD0A
000000000000
978123456789

After uncommenting the WHERE-restriction, the result is:

B002AACD0A
978123456789

I would have expected the result to be just 978123456789 since B002AACD0A is returned before 000000000000 when running the query without restriction.

How can this behavior be explained? And how am I supposed to sort and compare varchars so that they can work together like I can do with integers?

Funny enough, when changing the restriction to x>'B002AACD0A', the result is empty. Changing it tox>978123456789 returns B002AACD0A.

I.e. when comparing:

B002AACD0A > 978123456789 > 000000000000

But when sorting:

978123456789 > 000000000000 > B002AACD0A

When using binary sort explicitely (order by NLSSORT(x,'NLS_SORT=BINARY_AI')), the result is B002AACD0A>978123456789>000000000000 and matches the behavior of comparison. But I still do not know why this is happening.

oracle-database sorting compare
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