Problems with group by ... order by
От | John D. Burger |
---|---|
Тема | Problems with group by ... order by |
Дата | |
Msg-id | 1307c6f5709cab391e87d78e6744f605@mitre.org обсуждение исходный текст |
Ответы |
Re: Problems with group by ... order by
Re: Problems with group by ... order by |
Список | pgsql-general |
I can't figure out why the following doesn't work: select (case when count1 < 300 then 'Other' else country1 end) as country2, sum(count1) as count2 from (select coalesce(country, 'None') as country1, count(*) as count1 from userProfiles group by country1) as counts1 group by country2 order by (country2 = 'Other'), count2 desc Basically, I want to get an aggregate count of users across countries (including the "None" country), then I want to aggregate those countries with counts less than 300 into an Other pseudo-country. I want it sorted by this final count, except I want the Other entry to be last. This works fine if I leave out the first order-by condition - the result is sorted by the final count. But with the query as written above, I get: ERROR: column "country2" does not exist It also works fine if I just order by country2, count2 - it seems to be the comparison that's the problem. And ordering by a boolean after aggregating works fine in this simpler case: select country, count(*) as cnt from userProfiles group by country order by country is null, cnt; This puts the NULL count at the end. This is with PG 7.4.7. Any advice appreciated, including how to do this in a simpler fashion. - John Burger MITRE
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