Thinking outside the box

Patron Saint of Lost Yaks

posts - 202, comments - 734, trackbacks - 4

My Links

News

Post Categories

<< Why LEN differs from DATALENGTH when using BINARY data | Home | Another sequencing algorithm >>

How to tell if a number is a "POWER of 2"-number

SELECT Number,
        1 - SIGN(Number & (Number - 1))
FROM    master..spt_values
WHERE   Type = 'P'
        AND Number > 0

Other way is

CREATE FUNCTION dbo.isPowerOf2
(
      @i INT
)
RETURNS BIT
AS
BEGIN
      DECLARE @x FLOAT

      SET @x = LOG(Number) / LOG(2)

      RETURN      CASE
                  WHEN FLOOR(@x) = CEILING(@x) THEN 1
                  ELSE 0
            END
END

Feedback

# re: How to tell if a number is a "POWER of 2"-number

Is that first query will work for the number
524288 which is 2 power 19. it will not work for that number. that query has a limitation. it will work only for the values which are in that table. table records are finite. but 2 power numbers are infinite.

8/13/2008 7:15 AM | RamiReddy

Comments have been closed on this topic.