From: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
---|---|
To: | linasvepstas(at)gmail(dot)com |
Cc: | "pgsql-bugs(at)postgresql(dot)org" <pgsql-bugs(at)postgresql(dot)org> |
Subject: | Re: BUG #14494: Regression - Null arrays are not queryable |
Date: | 2017-01-13 21:10:03 |
Message-ID: | CAKFQuwb=n31=3F0DQDuWLRrjdLRQUrc7hSE_DYTFByrWyK5Lug@mail.gmail.com |
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Lists: | pgsql-bugs |
On Fri, Jan 13, 2017 at 11:38 AM, <linasvepstas(at)gmail(dot)com> wrote:
> The following bug has been logged on the website:
>
> Bug reference: 14494
> Logged by: Linas Vepstas
> Email address: linasvepstas(at)gmail(dot)com
> PostgreSQL version: 9.6.1
> Operating system: Debian unstable
> Description:
>
> Array handling appears to have regressed,
>
From what?
> with lots of surprising results for empty
> and null arrays.
>
>
>
> test=> select * from foo where outgoing=null;
> name | outgoing
> ------+----------
> (0 rows)
> unexpected: wanted one row here.
>
>
While you can configure the system to yield "true" for "null = null" by
default it does not - I suspect your prior system has this configuration
option turned on. This is not specific to arrays.
test=> select * from foo where outgoing != '{43,67}';
> name | outgoing
> ------+----------
> two | {}
> (1 row)
> unexpected: wanted two rows here. Where did the null row go?
>
Again, null != (non-null) yields null, not true, and would work this way
regardless of the option mentioned above...
> test=> select * from foo where array_length(outgoing,1)=0 ;
> name | outgoing
> ------+----------
> (0 rows)
>
> Huh? there is at least one array whose length is zero, and another that
> doesn't have a length...
>
Empty arrays and nulls, when provided to array_length, report NULL for all
dimensions.
David J.
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Previous Message | Andres Freund | 2017-01-13 21:05:08 | Re: BUG #14494: Regression - Null arrays are not queryable |