Re: Diffcult query
От | Lee Harr |
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Тема | Re: Diffcult query |
Дата | |
Msg-id | b5gn2l$1s2o$2@news.hub.org обсуждение исходный текст |
Ответ на | Diffcult query ("Dan Winslow" <d.winslow@cox.net>) |
Список | pgsql-sql |
In article <d9Iea.117330$JE5.48428@news2.central.cox.net>, Dan Winslow wrote: > Hi folks. This is giving me fits. I feel like it oughta be simple, but > apparantly its not...I think. > > Given a table : > > create table tablea ( > code1 varchar(32), > code2 varchar(32), > cost int > ); > > and the rows > > code1 code2 cost > ---------------------------------- > "aaa" "bbb" 2 > "ddd" "eee" 3 > "bbb" "aaa" 6 > "ggg" "hhh" 4 > > I need a ( preferably single ) query that will sum the costs for all unique > pairs of codes, without regard to column order. That is, for summing > purposes, rows 1 and 3 are identical, and should produce the sum of 8 for > the unordered pair("aaa","bbb"). It should also, of course, prevent the case > where ("bbb","aaa") is considered a seperate pair. Any ideas would be much > appreciated. > > Maybe you could create a function that will return all of the rows with a particular pair of codes. Then I think you could GROUP BY that function...
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