User Defined Function (UDF) to convert a given string to proper case

T-SQL has no built-in function to convert a string to proper case (In a proper case string, the first letter of each word would be in upper case. E.g: Bill Gates). So, I ended up writing my own PROPERCASE function.

****************************
Copyright © 2001 Narayana Vyas Kondreddi. All rights reserved.

Purpose: To convert a given string to proper case

Written by: Narayana Vyas Kondreddi
http://vyaskn.tripod.com

Tested on: SQL Server 2000

Date modified: December-5-2001 16:55 AM IST

Email: vyaskn@hotmail.com

Examples:

To convert the string 'william h gates' to proper case:
SELECT dbo.PROPERCASE('william h gates')

To convert the Notes field of titles table in pubs database to proper case:
SELECT dbo.PROPERCASE(notes) FROM pubs..titles
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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