Re: operators and bit field

Поиск
Список
Период
Сортировка
От Bruno Wolff III
Тема Re: operators and bit field
Дата
Msg-id 20030214213703.GA28014@wolff.to
обсуждение исходный текст
Ответ на operators and bit field  (Dennis Gearon <gearond@cvc.net>)
Ответы Re: operators and bit field
Re: operators and bit field
Список pgsql-general
On Fri, Feb 14, 2003 at 11:12:15 -0800,
  Dennis Gearon <gearond@cvc.net> wrote:
> I haven't seen what operators can be applied to bit masks.

It looks like & works:
area=> select 3&6;
 ?column?
----------
        2
(1 row)

>
> In particular, I am looking to use binary AND:
>
> I want to AND two bitmasks together and see:
>
>     A/ if the result has ANY bits set
>     B/ what bits are set in the results.
>
> SELECT other_fields
> FROM some_table
> WHERE
>       ( bitmask_8_columnA & bitmask_8_column B) = bitmask_8_patternONE
>    OR ( bitmask_8_columnA & bitmask_8_column B) = bitmask_8_patternTWO
> ;
>
> I may try to use a single char for one of the bit masks I need,
> is it possible to store all 256 values into a varchar(1) using
> escaped input?
>
> Is it possible to AND two varchars within a select and compare the result?
>
> SELECT other_fields
> FROM some_table
> WHERE ( varchar_1_columnA & varchar_1_columnB ) = 'single_escaped_char_string';
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
> http://archives.postgresql.org

В списке pgsql-general по дате отправления:

Предыдущее
От: Jonathan Bartlett
Дата:
Сообщение: Re: Inquiry From Form [pgsql]
Следующее
От: Jeffrey Baker
Дата:
Сообщение: Re: In 7.3.1, will I be able to reindex toast?