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From "Knut Anders Hatlen (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DERBY-6227) Distinct aggregates don't work well with territory-based collation
Date Fri, 24 May 2013 11:26:22 GMT
Knut Anders Hatlen created DERBY-6227:

             Summary: Distinct aggregates don't work well with territory-based collation
                 Key: DERBY-6227
                 URL: https://issues.apache.org/jira/browse/DERBY-6227
             Project: Derby
          Issue Type: Bug
          Components: SQL
    Affects Versions:
            Reporter: Knut Anders Hatlen

When working on DERBY-5840, I noticed that GroupedAggregateResultSet would do duplicate elimination
by comparing the java.lang.String representation of the values. With territory-based collation,
it is possible that two values that have different java.lang.String representation should
be considered duplicates, and this logic will produce incorrect results.


ij version 10.10
ij> connect 'jdbc:derby:memory:db;territory=en_US;collation=TERRITORY_BASED:PRIMARY;create=true';
ij> create table t(i int, s varchar(10));
0 rows inserted/updated/deleted
ij> insert into t values (1, 'a'), (1, 'a'), (2, 'b'), (2, 'B'), (3, 'a'), (3, 'A'), (3,
'b'), (3, 'B'), (3, 'c');
9 rows inserted/updated/deleted
ij> select distinct s from t;

3 rows selected
ij> select i, count(distinct s) from t group by i;
I          |2          
1          |1          
2          |2          
3          |5          

3 rows selected

I would have expected the last query to return

(1, 1)
(2, 1)
(3, 3)

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