Full-width conversion from SQL Server database to half-width

Copy codeThe Code is as follows:
Create function f_Convert (
@ Str NVARCHAR (4000), -- string to be converted
@ Flag bit -- Conversion flag. 0 is converted to halfwidth, and 1 is converted to fullwidth.
) RETURNS nvarchar (4000)
AS
BEGIN
DECLARE @ pat nvarchar (8), @ step int, @ I int, @ spc int
IF @ flag = 0
SELECT @ pat = n' % [! -~] % ', @ Step =-65248,
@ Str = REPLACE (@ str, n'', n '')
ELSE
SELECT @ pat = n' % [! -~] % ', @ Step = 65248,
@ Str = REPLACE (@ str, n'', n '')
SET @ I = PATINDEX (@ pat COLLATE LATIN1_GENERAL_BIN, @ str)
WHILE @ I> 0
SELECT @ str = REPLACE (@ str,
SUBSTRING (@ str, @ I, 1 ),
NCHAR (UNICODE (SUBSTRING (@ str, @ I, 1) + @ step ))
, @ I = PATINDEX (@ pat COLLATE LATIN1_GENERAL_BIN, @ str)
RETURN (@ str)
END
GO call: update table1 set column1 = dbo. f_Convert (column1, 0 );