SQL Server Url Decode函数

CREATE FUNCTION dbo.UrlDecode(@url varchar(3072))
RETURNS varchar(3072)
AS
BEGIN
DECLARE @count int, @c char(1), @cenc char(2), @i int, @urlReturn varchar(3072)
SET @count = Len(@url)
SET @i = 1
SET @urlReturn = ''
WHILE (@i <= @count)
BEGIN
SET @c = substring(@url, @i, 1)
IF @c LIKE '[!%]' ESCAPE '!'
BEGIN
SET @cenc = substring(@url, @i + 1, 2)
SET @c = CHAR(CASE WHEN SUBSTRING(@cenc, 1, 1) LIKE '[0-9]'
THEN CAST(SUBSTRING(@cenc, 1, 1) as int)
ELSE CAST(ASCII(UPPER(SUBSTRING(@cenc, 1, 1)))-55 as int)
END * 16 +
CASE WHEN SUBSTRING(@cenc, 2, 1) LIKE '[0-9]'
THEN CAST(SUBSTRING(@cenc, 2, 1) as int)
ELSE CAST(ASCII(UPPER(SUBSTRING(@cenc, 2, 1)))-55 as int)
END)
SET @urlReturn = @urlReturn + @c
SET @i = @i + 2
END
ELSE
BEGIN
SET @urlReturn = @urlReturn + @c
END
SET @i = @i +1
END
RETURN @urlReturn
END

CREATE FUNCTION dbo.fnDeURL
(
@URL VARCHAR(8000)
)
RETURNS VARCHAR(8000)
AS
BEGIN
DECLARE @Position INT,
@Base CHAR(16),
@High TINYINT,
@Low TINYINT,
@Pattern CHAR(21) SELECT @Base = '0123456789abcdef',
@Pattern = '%[%][0-9a-f][0-9a-f]%',
@URL = REPLACE(@URL, '+', ' '),
@Position = PATINDEX(@Pattern, @URL) WHILE @Position > 0
SELECT @High = CHARINDEX(SUBSTRING(@URL, @Position + 1, 1), @Base COLLATE Latin1_General_CI_AS),
@Low = CHARINDEX(SUBSTRING(@URL, @Position + 2, 1), @Base COLLATE Latin1_General_CI_AS),
@URL = STUFF(@URL, @Position, 3, CHAR(16 * @High + @Low - 17)),
@Position = PATINDEX(@Pattern, @URL) RETURN @URL
END