Re: Comparing bit in an integer field - Mailing list pgsql-general

From A. Kretschmer
Subject Re: Comparing bit in an integer field
Date
Msg-id 20091116142325.GD4331@a-kretschmer.de
Whole thread Raw
In response to Comparing bit in an integer field  (Amitabh Kant <amitabhkant@gmail.com>)
Responses Re: Comparing bit in an integer field  (Thom Brown <thombrown@gmail.com>)
Re: Comparing bit in an integer field  (Amitabh Kant <amitabhkant@gmail.com>)
List pgsql-general
In response to Amitabh Kant :
> Hello
>
> I need to compare the bit values of a integer field in my table. For example, I
> have a table called "t1" with just one field "a1" having following values:
>
> a1
> ==
> 0
> 12
> 8
> 0
> 1
> 10
> 7
> 19
>
> I am trying to fetch all records where the 3rd binary bit is 1, which from the
> above example should be 12 (00001100) and 7 (00000111). If I convert the values
> to binary and store it as string, I can easily compare them using substr, but
> would rather like to retain the integer field. I have tried using the get_bit
> function, but it seems my understanding of the function is not correct.

test=# select * from t1;
 a1
----
  0
 12
  8
  0
  1
 10
  7
 19
(8 rows)

test=*# select a1 from t1 where (a1>>2)::bit = B'1';
 a1
----
 12
  7
(2 rows)


Regards, Andreas
--
Andreas Kretschmer
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