Hi Knut, Thanks for the reply.
On Thu, Apr 29, 2010 at 11:53 PM, Knut Anders Hatlen <[email protected]> wrote: > On 04/29/10 05:16 PM, Nirmal Fernando wrote: >> 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? >> > > Hi Nirmal, > > I think this test case only attempts to demonstrate a bug that later was > logged as DERBY-4371. If you fix DERBY-4371, I find it quite reasonable > to update orderby.out to reflect that the query is now rejected. > > -- > Knut Anders > > -- Best Regards, Nirmal C.S.Nirmal J. Fernando Department of Computer Science & Engineering, Faculty of Engineering, University of Moratuwa, Sri Lanka.
