Scott, Shawn,

>The OP would like to detect that 4,5,6, and 7 are missing from the
>sequence. Your query would have only found that 7 was missing.

Right! For sequences longer than 1 you need something like...

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

PB

-----

SGreen@unimin.com wrote:

Peter,

Your query may work for data with single-row gaps (like his example data) but it will not work if the sequence skips more than one number.

Look at this sequence: 1,2,3,8,9,10

The OP would like to detect that 4,5,6, and 7 are missing from the sequence. Your query would have only found that 7 was missing.

Nice try, but sorry. It just won't meet the need.

Shawn Green
Database Administrator
Unimin Corporation - Spruce Pine


Peter Brawley <peter.brawley@earthlink.net> wrote on 08/18/2005 10:56:34 AM:

> Scott,
>
> >How do I execute a query that shows missing ID's like so:
>
> SELECT id AS i
> FROM tbl
> WHERE i <> 1 AND NOT EXISTS(
>   SELECT id FROM tbl WHERE id = i - 1
> );
>
> PB
>
> -----
>
> Scott Hamm wrote:

> If I got a table as follows:
>
>
> ID foo
> 1 12345
> 2 12346
> 4 12348
> 6 12349
> 7 12388
> 9 12390
> How do I execute a query that shows missing ID's like so:
>
> 3
> 5
> 8
>
> I wouldn't expect for it to show deleted data that was deleted, just show
> the "skipped" ID's.
>
> That way I determine if operator deleted too much (cheating at QC)
>
> Is it possible?
>  

>
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