Re: SQL subqueries newbie help
От | Rod Taylor |
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Тема | Re: SQL subqueries newbie help |
Дата | |
Msg-id | 1062868895.54737.3.camel@jester обсуждение исходный текст |
Ответ на | SQL subqueries newbie help (Alexei Chetroi <lexoid@lexa.uniflux-line.net>) |
Ответы |
Re: SQL subqueries newbie help
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Список | pgsql-sql |
> I'd like to write a query which returns following information regarding > each item: item, date of very first event, very last event. > Is this possible? I think I can write several SELECT queries and > procces them by an application or possibly write some procedure, but > what is better solution? Something like the below should do it: SELECT item , min_date , min_event , max_date , max_event FROM items JOIN (SELECT min(date) AS min_date , event AS min_event , item FROM events GROUP BY item) AS mn USING (item) JOIN (SELECT max(date)AS max_date , event AS max_event , item FROM events GROUP BY item) AS mx USING(item);
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