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From Daniel John Debrunner <...@apache.org>
Subject Re: territory-based collations and optimizations for the LIKE operator
Date Mon, 25 Aug 2008 20:36:41 GMT
Rick Hillegas wrote:

>> Rick, why do you believe that Derby will return a subset of the rows, 
>> it doesn't seem to follow from any of the other posts in this thread?
>>
>> Dan.
> Hi Dan,
> 
> Thanks for helping me puzzle through this. Consider the example we are 
> working with, a collation in which 'z' = 'xy'. What happens with the 
> following insert:
> 
>  insert into T(A) values ( 'zcb' ), ( 'xycb' )
> 
> followed by this query:
> 
>  select * from T where T.A like 'xy_b'
> 
> If I  understand what is being said, it seems like the following 
> happens: the ANSI rules return both rows but Derby returns only ( 'xycb' )

I thought Derby was following the ANSI rules for LIKE. From memory, LIKE 
operators on a character by character basis, not collation elements.

Dan.

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