MIME-Version: 1.0
Date: Sat, 19 Mar 2022 20:30:32 +0100
From: Paolo De Stefani <paolo@paolodestefani.it>
To: Christophe Pettus <xof@thebuild.com>
Cc: Psycopg <psycopg@postgresql.org>
Subject: Re: Query with boolean parameter
In-Reply-To: <FDFFF1ED-3355-4A1B-9EAE-53724D0EBA55@thebuild.com>
References: <8df15d1263aaa1a9d36eacb0e5b9a28e@paolodestefani.it>
 <74FC637F-2D25-4CD0-A075-9CB5293FCA5B@thebuild.com>
 <d88ac5f2ae2457bb2b97f98c47cfcdfc@paolodestefani.it>
 <FDFFF1ED-3355-4A1B-9EAE-53724D0EBA55@thebuild.com>
User-Agent: Roundcube Webmail/1.4.12
Message-ID: <6955bcd2bba7feaddb480df53fc8b558@paolodestefani.it>
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Archived-At: 
 <https://www.postgresql.org/message-id/6955bcd2bba7feaddb480df53fc8b558%40paolodestefani.it>
Precedence: bulk

Il 19/03/2022 17:35 Christophe Pettus ha scritto:
>> On Mar 19, 2022, at 05:10, Paolo De Stefani <paolo@paolodestefani.it> 
>> wrote:
>> Switching to psycopg 3 i have to consider many more differences than i 
>> expected
> 
> There have been some changes in the way psycopg2 does parameter
> substitution, although that one is an interesting case!  You might
> consider using IS DISTINCT FROM as Daniele suggested, or just =,
> depending on how you want nulls handled.

thanks to all for the suggestions i thimk i will use the '=' operator
what do you mean with 'depending on how you want nulls handled' ???

test4=# create table test (a text, b boolean);
CREATE TABLE
test4=# insert into test values ('aaa', true), ('bbb', false), ('ccc', 
null);
INSERT 0 3
test4=# select * from test;
   a  | b
-----+---
  aaa | t
  bbb | f
  ccc |
(3 rows)


test4=# select * from test where b = true;
   a  | b
-----+---
  aaa | t
(1 row)


test4=# select * from test where b is true;
   a  | b
-----+---
  aaa | t
(1 row)


test4=# select * from test where b = null;
  a | b
---+---
(0 rows)


test4=# select * from test where b is null;
   a  | b
-----+---
  ccc |
(1 row)

I will use '= True' or '= False' in psycopg cur.execute with parameter 
substitution and 'IS NULL' without parameter when i need to check the 
null value


-- 
Paolo De Stefani