Re: operators and bit field
От | Dennis Gearon |
---|---|
Тема | Re: operators and bit field |
Дата | |
Msg-id | EALH54FDLGLHJIPOOKTNTQKHBB9PKWV.3e4d6386@cal-lab обсуждение исходный текст |
Ответ на | Re: operators and bit field (Bruno Wolff III <bruno@wolff.to>) |
Список | pgsql-general |
Bruno, could you check that with explicity bitfield(n) values, please? 2/14/2003 1:37:03 PM, Bruno Wolff III <bruno@wolff.to> wrote: >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 >
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