RE: Sequential select queries...??

Поиск
Список
Период
Сортировка
От Henshall, Stuart - WCP
Тема RE: Sequential select queries...??
Дата
Msg-id E2870D8CE1CCD311BAF50008C71EDE8E01F74682@MAIL_EXCHANGE
обсуждение исходный текст
Ответ на Sequential select queries...??  (Mark Mikulec <mm98au@badger.ac.brocku.ca>)
Список pgsql-sql
If you want to know for each individual one wether both equal or not you
could do:
SELECT *,NOT ((name=description) IS NULL) AND (name=description) AS both
FROM t WHERE name='bleh' OR description='bleh';
If you wanted totals of the same you could do:
SELECT count(*) AS tot,NOT ((name=description) IS NULL) AND
(name=description) AS both FROM t WHERE name='bleh' OR description='bleh'
GROUP BY NOT ((name=description) IS NULL AND (name=description);
I think this should be more efficient than UNIONs, but am not an expert on
the query planner or executor.
- Stuart

> -----Original Message-----
> From:    Mark Mikulec [SMTP:mm98au@badger.ac.brocku.ca]
> Sent:    Wednesday, August 15, 2001 1:41 AM
> To:    pgsql-sql@postgresql.org
> Subject:    Sequential select queries...??
> 
> Hello,
> 
> At first I thought what I was trying to do was simple and could be done
> easily - but alas, I've spent way too much time and could not figure out
> how to get the results in question.
> 
> Let's say I have a table T comprised of  id of type integer, name and
> description both of type text.
> 
> What i'd like to do is the following:
> 
> Select id from T where name = 'bleh';
> 
> and
> 
> Select id from T where description = 'bleh';
> 
> and result both results in the same result set. That is, duplicate id's
> if they appear. So then I could do a GROUP BY and a COUNT to see how
> many appeared in only one, and how many appeared in both.
> 
> Could someone help me? I've tried countless different sql queries, can't
> seem to get one to work. If I can just get those duplicate id's in the
> query.. then I'd be laughing and then I can complete my task.
> 
> Thanks in advance,
> 
>     Mark
> 


В списке pgsql-sql по дате отправления:

Предыдущее
От: darcy@druid.net (D'Arcy J.M. Cain)
Дата:
Сообщение: Re: Primary vs Unique Index
Следующее
От: Tom Lane
Дата:
Сообщение: Re: database location question