[T-SQL] Proper case function in SQL Server

CREATE FUNCTION PROPERCASE
(
--The string to be converted to proper case
@input varchar(8000)
)
--This function returns the proper case string of varchar type
RETURNS varchar(8000)
AS
BEGIN
IF @input IS NULL
BEGIN
--Just return NULL if input string is NULL
RETURN NULL
END
--Character variable declarations
DECLARE @output varchar(8000)
--Integer variable declarations
DECLARE @ctr int, @len int, @found_at int
--Constant declarations
DECLARE @LOWER_CASE_a int, @LOWER_CASE_z int, @Delimiter char(3), @UPPER_CASE_A int, @UPPER_CASE_Z int
--Variable/Constant initializations
SET @ctr = 1
SET @len = LEN(@input)
SET @output = ''
SET @LOWER_CASE_a = 97
SET @LOWER_CASE_z = 122
SET @Delimiter = ' '
SET @UPPER_CASE_A = 65
SET @UPPER_CASE_Z = 90
WHILE @ctr <= @len
BEGIN
--This loop will take care of reccuring white spaces
WHILE CHARINDEX(SUBSTRING(@input,@ctr,1), @Delimiter) > 0
BEGIN
SET @output = @output + SUBSTRING(@input,@ctr,1)
SET @ctr = @ctr + 1
END
IF ASCII(SUBSTRING(@input,@ctr,1)) BETWEEN @LOWER_CASE_a AND @LOWER_CASE_z
BEGIN
--Converting the first character to upper case
SET @output = @output + UPPER(SUBSTRING(@input,@ctr,1))
END
ELSE
BEGIN
SET @output = @output + SUBSTRING(@input,@ctr,1)
END
SET @ctr = @ctr + 1
WHILE CHARINDEX(SUBSTRING(@input,@ctr,1), @Delimiter) = 0 AND (@ctr <= @len)
BEGIN
IF ASCII(SUBSTRING(@input,@ctr,1)) BETWEEN @UPPER_CASE_A AND @UPPER_CASE_Z
BEGIN
SET @output = @output + LOWER(SUBSTRING(@input,@ctr,1))
END
ELSE
BEGIN
SET @output = @output + SUBSTRING(@input,@ctr,1)
END
SET @ctr = @ctr + 1
END
END
RETURN @output
END