MSSQL BIT_COUNT (Hammingdistance)

mysql, sql, sql-server

Solution

Why not just write your own bit_count code in T-SQL? There's no need to use SQL CLR if all you need is to count the number of set bits in a bigint. Here is an example:

CREATE FUNCTION bit_count
(
   @pX bigint
)
RETURNS int
AS
BEGIN
   DECLARE @lRet integer
   SET @lRet = 0
   WHILE (@pX != 0)
   BEGIN
      SET @lRet = @lRet + (@pX & 1)
      SET @pX = @pX / 2
   END   
   return @lRet   
END
GO

Also, here's a fiddle you can try to see this function in action.

Be advised that this algorithm only works on non-negative bigints. If you are looking for an algorithm that works on negative bigints, see this link.

Problem

Is there any function similar to the MYSQL `BIT_COUNT` function in MSSQL? I want to create a very simple Hammingdistance function in MSSQL that i can use in my selects. Here is what i have for MYSQL: ``` CREATE FUNCTION `HAMMINGDISTANCE`(`hasha` BIGINT, `hashb` BIGINT) RETURNS int(11) DETERMINISTIC RETURN BIT_COUNT(hasha^hashb) ```

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