select min(number)
from Common.dbo.Numbers
left outer join dbo.Table
	on number = id
where id is null
and number > 0

SELECT MIN(Number) 
FROM dbo.GetNumbers(0, 9999) 
left outer join dbo.Table
	on number = id
WHERE id is null

SET STATISTICS TIME ON
GO
DECLARE @BitBucket INT
--=============================================================================
PRINT REPLICATE('=',100)
PRINT 'Itzek''s method:'
;WITH
L0 AS (SELECT 1 AS C UNION ALL SELECT 1), --2 rows
L1 AS (SELECT 1 AS C FROM L0 AS A, L0 AS B),--4 rows
L2 AS (SELECT 1 AS C FROM L1 AS A, L1 AS B),--16 rows
L3 AS (SELECT 1 AS C FROM L2 AS A, L2 AS B),--256 rows
L4 AS (SELECT 1 AS C FROM L3 AS A, L3 AS B),--65536 rows
L5 AS (SELECT 1 AS C FROM L4 AS A, L4 AS B),--4294967296 rows
num AS (SELECT ROW_NUMBER() OVER(ORDER BY C) AS N FROM L5)
SELECT @BitBucket = N FROM NUM WHERE N <= 1000000;

--=============================================================================
PRINT REPLICATE('=',100)
PRINT 'Jeff Moden''s Method'
;  WITH cTally AS
(-----------------------------------------------------------------------------
 --==== High performance CTE equivalent of a Tally or Numbers table
 SELECT TOP (1000000)
        ROW_NUMBER() OVER (ORDER BY t1.ID) AS N
   FROM Master.sys.SysColumns t1
  CROSS JOIN Master.sys.SysColumns t2
)-----------------------------------------------------------------------------
SELECT @BitBucket = N FROM cTally --Do your outer join with table being checked here
PRINT REPLICATE('=',100)

 CREATE FUNCTION dbo.fnTally
/****************************************************************************************
 Purpose:
 Given a range of Integers not exceeding a count of 121 million, return the range of
 numbers as a table.

 Notes: Preserved as an "inline" single statement function for sheer performance.
        Therefore, no error checking, etc.

 Revision History:
 Rev 00 - 23 Dec 2005 - Jeff Moden - Initial creation and unit test
****************************************************************************************/
--===== Declare the parameters
        (
        @piStartNumber INT,
        @piEndNumber   INT
        )
RETURNS TABLE
     AS     
 RETURN (WITH cTally AS
        (--------------------------------------------------------------------------------
         --==== High performance CTE equivalent of a Tally or Numbers table
         SELECT TOP (@piEndNumber-@piStartNumber+1)
                ROW_NUMBER() OVER (ORDER BY t1.ID) AS Number
           FROM Master.sys.SysColumns t1
          CROSS JOIN Master.sys.SysColumns t2
        )--------------------------------------------------------------------------------
         SELECT N = Number+@piStartNumber-1 FROM cTally
        )