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Identity gap

Author

Topic

noamg
Posting Yak Master

215 Posts

Posted - 2007-06-07 : 03:29:23

I need to find the gap-range of an integer columns
for example:

create table Nums( num int )
insert into Nums select 1
insert into Nums select 2
insert into Nums select 4
insert into Nums select 7
insert into Nums select 8

the result: fromNum toNum
3, 3
5, 6

thanks

Noam Graizer

mwjdavidson
Aged Yak Warrior

735 Posts

Posted - 2007-06-07 : 04:24:02

Try this:

--Create table variable
DECLARE @gaps TABLE(id INT)

--Insert test data
INSERT INTO @gaps
SELECT 1
UNION ALL SELECT 2
UNION ALL SELECT 4
UNION ALL SELECT 5
UNION ALL SELECT 8
UNION ALL SELECT 9

SELECT      gap_start.id + 1    AS FromNum, 
            MIN(gap_end.id) -1  AS ToNum
FROM    (   SELECT  g1.id
            FROM    @gaps AS g1
            WHERE   NOT EXISTS (SELECT * FROM @gaps AS g2 WHERE g2.id = g1.id + 1)
        )   AS gap_start
JOIN    (
            SELECT  g1.id
            FROM    @gaps AS g1
            WHERE   NOT EXISTS (SELECT * FROM @gaps AS g2 WHERE g2.id = g1.id - 1)
        )   AS gap_end
ON          gap_start.id < gap_end.id
GROUP BY    gap_start.id

Mark

noamg
Posting Yak Master

215 Posts

Posted - 2007-06-07 : 04:34:46

many thanks !

Noam Graizer

mwjdavidson
Aged Yak Warrior

735 Posts

Posted - 2007-06-07 : 04:57:15

No problem

Mark

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