SQL Server - Remove all non-printable ASCII characters

问题

We recently migrated from SQL Server 2012 to SQL Server 2014 and all our FOR XML code started throwing errors about non-printable ASCII characters. I wrote this horrible function to remove non-printable ASCII characters as a quick fix. I want to replace it with something cleaner. Is there a way to do this?

ALTER FUNCTION [dbo].[remove_non_printable_chars]
(@input_string nvarchar(max))
RETURNS nvarchar(max)
BEGIN
    RETURN
    REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
    REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
    REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(
    REPLACE(REPLACE(@input_string,
        CHAR(1), ''),CHAR(2), ''),CHAR(3), ''),CHAR(4), ''),CHAR(5), ''),CHAR(6), ''),CHAR(7), ''),CHAR(8), ''),CHAR(9), ''),CHAR(10), ''),
        CHAR(11), ''),CHAR(12), ''),CHAR(13), ''),CHAR(14), ''),CHAR(15), ''),CHAR(16), ''),CHAR(17), ''),CHAR(18), ''),CHAR(19), ''),CHAR(20), ''),
        CHAR(21), ''),CHAR(22), ''),CHAR(23), ''),CHAR(24), ''),CHAR(25), ''),CHAR(26), ''),CHAR(27), ''),CHAR(28), ''),CHAR(29), ''),CHAR(30), ''),
        CHAR(31), ''), NCHAR(0) COLLATE Latin1_General_100_BIN2, '')
END

Here's the FOR XML code that broke. (I did not write this. It was already in the code base).

SELECT @HTMLTableData =
(
    SELECT  HTMLRows 
    FROM (
        SELECT N'<tr>' + HTMLRow + N'</tr>' AS HTMLRows 
        FROM @HTMLRowData
    ) mi            
    FOR XML PATH(''), TYPE
).value('/', 'NVARCHAR(MAX)')

回答1:

Another Option.

This function will replace control characters and correct any residual repeating spaces. For example Jane Smith{13}was here will not be returned as Jane Smithwas here, but rather Jane Smith was here

CREATE FUNCTION [dbo].[udf-Str-Strip-Control](@S varchar(max))
Returns varchar(max)
Begin
    ;with  cte1(N) As (Select 1 From (Values(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)) N(N)),
           cte2(C) As (Select Top (32) Char(Row_Number() over (Order By (Select NULL))-1) From cte1 a,cte1 b)
    Select @S = Replace(@S,C,' ')
     From  cte2

    Return ltrim(rtrim(replace(replace(replace(@S,' ','†‡'),'‡†',''),'†‡',' ')))
End
--Select [dbo].[udf-Str-Strip-Control]('Michael        '+char(13)+char(10)+'LastName')  --Returns: Michael LastName

回答2:

In-line version:

create function [dbo].[remove_non_printable_chars] (@input_string nvarchar(max))
returns table with schemabinding as return (
  select 
    replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(
    replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(
    replace(replace(replace(replace(replace(replace(replace(replace(replace(replace(
    replace(replace(@input_string collate latin1_general_100_bin2,
        char(1), ''),char(2), ''),char(3), ''),char(4), ''),char(5), ''),char(6), ''),char(7), ''),char(8), ''),char(9), ''),char(10), ''),
        char(11), ''),char(12), ''),char(13), ''),char(14), ''),char(15), ''),char(16), ''),char(17), ''),char(18), ''),char(19), ''),char(20), ''),
        char(21), ''),char(22), ''),char(23), ''),char(24), ''),char(25), ''),char(26), ''),char(27), ''),char(28), ''),char(29), ''),char(30), ''),
        char(31), ''), char(0) , '') 
     as clean_string
);
go

And use it like so:

select c.clean_string
from dbo.remove_non_printable_chars(@dirtystring) c

select ...
  , c.clean_string
from t
  cross apply dbo.remove_non_printable_chars(t.dirty_string) c

Reference:

When is a SQL function not a function? "If it’s not inline, it’s rubbish." - Rob Farley
Inline Scalar Functions - Itzik Ben-Gan
Scalar functions, inlining, and performance: An entertaining title for a boring post - Adam Machanic
TSQL User-Defined Functions: Ten Questions You Were Too Shy To Ask - Robert Sheldon

回答3:

Just extending the previous answers a little bit

Below the white-list characters, all the others chars will be cleared

[ !`"#$%&'()\*+,\-\./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ\[\]^``\\_abcdefghijklmnopqrstuvwxyz{|}~µº°¡¢£¤¥¦§¨©ª«¬®¯±²³´¶·¸¹»¼½¾¿×÷ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿ]

I know it's ugly but it works.

CREATE FUNCTION [dbo].REPLACE_UNPRINT_CHARS(@VarString nvarchar(256))  
RETURNS nvarchar(256) 
AS    
BEGIN  
    RETURN REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(@VarString, CHAR(0), ''), CHAR(1), ''), CHAR(2), ''), CHAR(3), ''), CHAR(4), ''), CHAR(5), ''), CHAR(6), ''), CHAR(7), ''), CHAR(8), ''), CHAR(9), ''), CHAR(10), ''), CHAR(11), ''), CHAR(12), ''), CHAR(13), ''), CHAR(14), ''), CHAR(15), ''), CHAR(16), ''), CHAR(17), ''), CHAR(18), ''), CHAR(19), ''), CHAR(20), ''), CHAR(21), ''), CHAR(22), ''), CHAR(23), ''), CHAR(24), ''), CHAR(25), ''), CHAR(26), ''), CHAR(27), ''), CHAR(28), ''), CHAR(29), ''), CHAR(30), ''), CHAR(31), ''), CHAR(127), ''), CHAR(128), ''), CHAR(129), ''), CHAR(130), ''), CHAR(131), ''), CHAR(132), ''), CHAR(133), ''), CHAR(134), ''), CHAR(135), ''), CHAR(136), ''), CHAR(137), ''), CHAR(138), ''), CHAR(139), ''), CHAR(140), ''), CHAR(141), ''), CHAR(142), ''), CHAR(143), ''), CHAR(144), ''), CHAR(145), ''), CHAR(146), ''), CHAR(147), ''), CHAR(148), ''), CHAR(149), ''), CHAR(150), ''), CHAR(151), ''), CHAR(152), ''), CHAR(153), ''), CHAR(154), ''), CHAR(155), ''), CHAR(156), ''), CHAR(157), ''), CHAR(158), ''), CHAR(159), ''), CHAR(160), ''); 
END;

Use for data clean up

UPDATE [dnName].[dbo].[tableName] 
SET FieldDirtyData= dbo.REPLACE_UNPRINT_CHARS(FieldDirtyData)
WHERE PATINDEX('%['+CHAR(1)+CHAR(2)+CHAR(3)+CHAR(4)+CHAR(5)+CHAR(6)+CHAR(7)+CHAR(8)+CHAR(9)+CHAR(10)+CHAR(11)+CHAR(12)+
CHAR(13)+CHAR(14)+CHAR(15)+CHAR(16)+CHAR(17)+CHAR(18)+CHAR(19)+CHAR(20)+
CHAR(21)+CHAR(22)+CHAR(23)+CHAR(24)+CHAR(25)+CHAR(26)+CHAR(27)+CHAR(28)+CHAR(29)+CHAR(30)+CHAR(31)+CHAR(127)+
CHAR(128)+CHAR(129)+CHAR(130)+CHAR(131)+CHAR(132)+CHAR(133)+CHAR(134)+CHAR(135)+CHAR(136)+CHAR(137)+CHAR(138)+
CHAR(139)+CHAR(140)+CHAR(141)+CHAR(142)+CHAR(143)+CHAR(144)+CHAR(145)+CHAR(146)+CHAR(147)+CHAR(148)+CHAR(149)+CHAR(150)+
CHAR(151)+CHAR(152)+CHAR(153)+CHAR(154)+CHAR(155)+CHAR(156)+CHAR(157)+CHAR(158)+CHAR(159)+CHAR(160)+']%', FieldDirtyData) <> 0

Adjust your datatype (nvarchar or varchar + max) as required

If you want to add more chars to clear use "select ASCII('char to remove here')" MSSQL command in order to get the ASCII code of the char and put it inside the replace instruction

i.g SELECT ASCII('¢') returns 162

so add one more "REPLACE(" after "RETURN" and "CHAR(162), '')" at the end of line but before the ";" sign.

来源：https://stackoverflow.com/questions/43148767/sql-server-remove-all-non-printable-ascii-characters

标签

sql-server

sql-server-2014