Re: SQL subqueries newbie help
| От | Rod Taylor |
|---|---|
| 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
|
| 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);
В списке pgsql-sql по дате отправления: