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From:Jerry Schwartz Date:October 8 2008 8:28pm
Subject:RE: Finding gaps
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I'm finally getting back to this issue, and I've read the bits on
artfulsoftware. The example

SELECT
  a.id+1 AS 'Missing From',
  MIN(b.id) - 1 AS 'To'
FROM tbl AS a, tbl AS b
WHERE a.id < b.id
GROUP BY a.id
HAVING a.id < MIN(b.id) - 1;

Looks like exactly what I want. However, when I try it (prod is my tbl,
prod_num is my id) I get

mysql> select a.prod_num + 1 AS `Missing From`,
    ->   MIN(b.prod_num - 1) AS `To`
    -> from prod as a, prod as b
    -> where a.prod_num < b.prod_num
    -> group by a.prod_num
    -> having a.prod_num < min(b.prod_num) -1 ;
ERROR 1054 (42S22): Unknown column 'a.prod_num' in 'having clause'

I must be missing something obvious; or does this not work in 4.1.22?

Regards,
Jerry Schwartz
The Infoshop by Global Information Incorporated
195 Farmington Ave.
Farmington, CT 06032
860.674.8796 / FAX: 860.674.8341
www.the-infoshop.com
www.giiexpress.com
www.etudes-marche.com

>-----Original Message-----
>From: Peter Brawley [mailto:peter.brawley@stripped]
>Sent: Wednesday, September 17, 2008 5:26 PM
>To: Stut; mysql@stripped
>Subject: Re: Finding gaps
>
> >Is there any elegant way of finding the gaps?
>
>You'll find some ideas under (and near) "Find missing numbers in a
>sequence" at http://www.artfulsoftware.com/infotree/queries.php.
>
>PB
>
>-----
>
>Stut wrote:
>> On 17 Sep 2008, at 22:12, Jerry Schwartz wrote:
>>> I have records that should be sequentially (not auto-increment)
>>> numbered,
>>> but there are gaps. Is there any elegant way of finding the gaps?
>>
>> Why do they need to be sequential? When this requirement comes up it's
>> usually for illogical reasons.
>>
>> -Stut
>>
>> ----------------------------------------------------------------------
>--
>>
>>
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>9/17/2008 5:07 PM
>>
>>



Thread
Finding gapsJerry Schwartz17 Sep
  • Re: Finding gapsStut17 Sep
    • Re: Finding gapsPeter Brawley17 Sep
      • RE: Finding gapsJerry Schwartz8 Oct
        • Re: Finding gapsGerald L. Clark8 Oct
          • RE: Finding gapsUS Data Export8 Oct
        • Re: Finding gapsPeter Brawley8 Oct
          • RE: Finding gapsUS Data Export9 Oct
            • Re: Finding gapsPeter Brawley9 Oct
              • RE: Finding gapsJerry Schwartz10 Oct
                • Re: Finding gapsMoon's Father25 Oct
                  • Re: Finding gapsMoon's Father25 Oct
                  • RE: Finding gapsUS Data Export27 Oct
    • RE: Finding gapsJerry Schwartz17 Sep
      • Re: Finding gapsStut18 Sep
        • Re: Finding gapsMr. Shawn H. Corey18 Sep
        • RE: Finding gapsJerry Schwartz18 Sep
          • Re: Finding gapsMike Diehl18 Sep
            • RE: Finding gapsJerry Schwartz18 Sep
    • RE: Finding gapsMartin Gainty18 Sep
      • RE: Finding gapsJerry Schwartz18 Sep
    • Re: Finding gapsJoerg Bruehe18 Sep
    • Re: Finding gapsJoerg Bruehe18 Sep
      • Re: Finding gapsStut18 Sep
        • Re: Finding gapsMr. Shawn H. Corey18 Sep