Re: UNION versus SUB SELECT

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От
Merlin Moncure
Тема
Re: UNION versus SUB SELECT
Дата
Msg-id
CAHyXU0xGAO3rOoMQPmd4Otw98JHWOnZvrWbmQLVgWyzqiJGE1Q@mail.gmail.com
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Дерево обсуждения
UNION versus SUB SELECT Robert DiFalco <robert.difalco@gmail.com>
Re: UNION versus SUB SELECT desmodemone <desmodemone@gmail.com>
Re: UNION versus SUB SELECT Robert DiFalco <robert.difalco@gmail.com>
Re: UNION versus SUB SELECT desmodemone <desmodemone@gmail.com>
Re: UNION versus SUB SELECT Robert DiFalco <robert.difalco@gmail.com>
Re: UNION versus SUB SELECT Merlin Moncure <mmoncure@gmail.com>
Re: UNION versus SUB SELECT Robert DiFalco <robert.difalco@gmail.com>
On Thu, Nov 21, 2013 at 2:31 PM, desmodemone  wrote:
> Hi Robert, could you try with "exists" ?
>
> SELECT c.*
> FROM contacts c
> WHERE  exists  ( SELECT  1 FROM phone p WHERE p.addr =? and
> p.contact_id=c.id )
> OR exists (SELECT  1 FROM email e WHERE e.addr = ? and  e.contact_id=c.id );

hm, how about:
SELECT c.*
FROM contacts c
WHERE  exists  (
  SELECT  1
  FROM phone p
  WHERE p.addr =? AND p.contact_id=c.id
  UNION ALL
  SELECT  1 FROM email e
  WHERE e.addr = ? AND e.contact_id=c.id
);

merlin

В списке pgsql-performance по дате отправления
От: Rogerio Pereira
Дата:
Сообщение: Re: Query in cache
От: Robert DiFalco
Дата:
Сообщение: Re: UNION versus SUB SELECT
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