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From Nirmal Fernando <nirmal070...@gmail.com>
Subject Test case in orderby.out file
Date Thu, 29 Apr 2010 15:16:08 GMT
Hi All,
I think behaviour of following test is not valid, since
ColumnReference age is not there in the distinct list.
line:1810 of orderby.out

ij> -- Ordering by an expression involving an unselected column is not. However,
-- Derby does not currently enforce this restriction. Note that the answer
-- that Derby returns is incorrect: Derby returns two rows with duplicate
-- 'name' values. This is because Derby currently implicitly includes the
-- 'age' column into the 'distinct' processing due to its presence in the
-- ORDER BY clause. DERBY-2351 and DERBY-3373 discuss this situation in
-- more detail.
select distinct name from person order by age*2;
NAME
----------
John
Mary
John

Can someone explain this behaviour?

Thanks.

--
Best Regards,
Nirmal

C.S.Nirmal J. Fernando
Department of Computer Science & Engineering,
Faculty of Engineering,
University of Moratuwa,
Sri Lanka.

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