SQL Server function Compare two string C# equivalents

Compares substrings of two specified string and returns an integer that indicates their relative position in the sort order in SQL server. It is same as CompareOrdinal and CompareTo in C# or VB.Net:

CREATE FUNCTION [dbo].[Compare] (

      @StrA NVARCHAR(MAX)

      ,@StrB NVARCHAR(MAX)

      ,@IndexA INT = 1

      ,@IndexB INT = 1

      ,@Length INT = NULL

      ,@ignoreCase BIT = 0

      )

RETURNS INT

AS

BEGIN

      DECLARE @SubStrA NVARCHAR(MAX)

      DECLARE @SubStrB NVARCHAR(MAX)

      DECLARE @UniCodeA AS INT

      DECLARE @UniCodeB AS INT

      IF @Length IS NULL

            SET @Length = LEN(@StrA) + LEN(@StrB)

      IF @ignoreCase = 1

      BEGIN

            SET @SubStrA = LOWER(SUBSTRING(@StrA, @IndexA, @Length))

            SET @SubStrB = LOWER(SUBSTRING(@StrB, @IndexB, @Length))

      END

      ELSE

      BEGIN

            SET @SubStrA = SUBSTRING(@StrA, @IndexA, @Length)

            SET @SubStrB = SUBSTRING(@StrB, @IndexB, @Length)

      END

      SET @UniCodeA = UNICODE(@SubStrA)

      SET @UniCodeB = UNICODE(@SubStrB)

      WHILE @UniCodeA = @UniCodeB

      BEGIN

            SET @SubStrA = STUFF(@SubStrA, 1, 1, '')

            SET @SubStrB = STUFF(@SubStrB, 1, 1, '')

            SET @UniCodeA = UNICODE(@SubStrA)

            SET @UniCodeB = UNICODE(@SubStrB)

      END

      RETURN ISNULL(@UniCodeA, 0) - ISNULL(@UniCodeB, 0)

END

Example:

SELECT dbo.Compare('a', 'A', DEFAULT, DEFAULT, DEFAULT, DEFAULT)

Output: 32