Advanced SQL Server Function for Proper Case Conversion

This article details a robust SQL Server function designed to convert uppercase text to proper case while addressing complexities such as non-English characters and varying whitespace. The function offers several key advantages:

• Handles Whitespace Variations: Correctly handles multiple spaces and various whitespace characters (including line breaks, tabs, and non-breaking spaces).
• Supports Non-English Alphabets: Accurately processes text containing characters from alphabets beyond English.
• Maintains Lowercase Words: Preserves any existing lowercase words within the input string.
• Version Compatibility: Functions across different SQL Server versions.
• Customizable Whitespace: The whitespace definition is configurable, allowing for tailored handling.

Function Implementation:

CREATE FUNCTION ToProperCase(@string VARCHAR(255)) RETURNS VARCHAR(255)
AS
BEGIN
  DECLARE @i INT;           -- Index
  DECLARE @l INT;           -- Input Length
  DECLARE @c NCHAR(1);      -- Current Character
  DECLARE @f INT;           -- First Letter Flag (1/0)
  DECLARE @o VARCHAR(255);  -- Output String
  DECLARE @w VARCHAR(10);   -- Whitespace Characters

  SET @w = '['   CHAR(13)   CHAR(10)   CHAR(9)   CHAR(160)   ' '   ']';
  SET @i = 1;
  SET @l = LEN(@string);
  SET @f = 1;
  SET @o = '';

  WHILE @i  0
    BEGIN
      SET @f = 1;
      SET @o = @o   @c;
    END
    ELSE
    BEGIN
      IF @f = 1
      BEGIN
        SET @o = @o   UPPER(@c);
        SET @f = 0;
      END
      ELSE
        SET @o = @o   LOWER(@c);
    END
    SET @i = @i   1;
  END
  RETURN @o;
END;

Usage Example:

SELECT dbo.ToProperCase('ALL UPPER CASE and    SOME lower ÄÄ ÖÖ ÜÜ ÉÉ ØØ ĈĈ ÆÆ');

Example Output:

All Upper Case and Some lower Ää Öö Üü Éé Øø Cc Ææ