Re: difficult query
От | Masaru Sugawara |
---|---|
Тема | Re: difficult query |
Дата | |
Msg-id | 20020505061938.1E8A.RK73@sea.plala.or.jp обсуждение исходный текст |
Ответ на | Re: difficult query (Jakub Ouhrabka <jouh8664@ss1000.ms.mff.cuni.cz>) |
Список | pgsql-sql |
On Sat, 4 May 2002 19:34:03 +0200 (CEST) Jakub Ouhrabka <jouh8664@ss1000.ms.mff.cuni.cz> wrote: > > Basically, no. (You might be able to do it with the help > > of a user-defined function though). I also think so. > yesterday when I faced this problem (which can be solved perfectly with > the outer join) I wasn't able to remember the solution... If there is > any... Just out of curiosity... I wouldn't think that that can be always solved. Whether it can be or notdepends on the elements of "day" column. But untilits aggregation will lack two successive numbers or more, the following query is useful,I guess. CREATE VIEW v_table1 AS SELECT tt.day , COUNT(tt.data) AS data FROM (SELECT t.day, t.data FROM table1 AS t UNIONALL SELECT 1, NULL -- indispensable if there's no row of day=1. )AS tt GROUP BY tt.day ; SELECT t0.day, t0.data FROM v_table1 AS t0 UNION SELECT t1.day - 1 , 0 FROM v_table1 AS t1, v_table1 AS t2 WHERE t1.day > t2.day GROUP BY t1.day HAVING t1.day> MAX(t2.day) + 1 ; In addition, until its aggregation will lack THREE ones or more, ... SELECT t0.day, t0.data FROM v_table1 AS t0 UNION SELECT t1.day - 1, 0 FROM ... UNION SELECT t3.day - 2, 0 FROM ... Regards, Masaru Sugawara
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