Thread

Re: [BUGS] General Bug Report: GROUP BY with NULL not done properly(Oracle8& DB/2 do this completely different)

secret <secret@kearneydev.com> — 1999-07-08T16:00:27Z

>
>
> When i make the following table:
>
> a|b| c
> -+-+--
> 1|1|10
> 1|2|10
> 1|2| 5
> 2|2|15
> 2|2|-3
> 2|1|50
> 2| |25
> 2| |15
> 1| |34
> 1| |54
>  | | 5
>  | | 7
>  |1| 7
>  |4| 7
>  |4| 7
> (15 rows)
>
> And do the following query, I get what i think was desired,
> the null/null, null/4, 1/null, 2/null are grouped together into a single
> output row...
>
> sszabo=> select a,b,sum(c) from b group by a,b;
> a|b|sum
> -+-+---
> 1|1| 10
> 1|2| 15
> 1| | 88
> 2|1| 50
> 2|2| 12
> 2| | 40
>  |1|  7
>  |4| 14
>  | | 12
> (9 rows)
>
> sszabo=> select version();
> version
> --------------------------------------------------------------------
> PostgreSQL 6.5.0 on i386-unknown-freebsd3.1, compiled by gcc 2.7.2.1

    Smaller examples I try work too under v6.5, but here is an example from a larger one:

SELECT a,b,sum(c) FROM xx GROUP BY a,b ORDER BY a,b;
a    | b        |  sum
..
     |102060|    6
      |102060|    1
      |102060|    6
      |102060|    6
      |102060|    0
      |102060|    6
      |102061|    6
      |102061|    6
      |102061|    6
      |102061|    6
      |102061|    7
      |102084|   10
      |102084|   10
      |102084|   10
      |102085|    4
      |102109|   18
      |102109|   18
      |102109|   54
      |102109|   18
      |102110|    1
      |102110|    1

There are actually 65,000 rows, so I can't quote all of them, but I will give you a dump of the
test table upon request so you can duplicate the results... Here are a couple queries that
illustrate the errors:
ftc=> select count(*) from xx where b=102110;
count
-----
    2
(1 row)

ftc=> select count(*) from xx where a is null and b=102110;
count
-----
    2
(1 row)

    As you see above, the GROUP on a didn't function for b=102110, we have 2 rows, both of which
were returned, both of which A is NULL.  If you'd like a dump of this table I'll send it to you and
not cc the list on it...  It's a stripped down version of another table I use quite a bit.

Version: [PostgreSQL 6.5.0 on i586-pc-linux-gnulibc1, compiled by gcc 2.7.2.1]

David Secret
MIS Director
Kearney Development Co., Inc.