T-SQL select special characters from nvarchar field - sql

Question

I'm looking for a select statement in which I can refine values in a nvarchar field.
For example: the input value is '!ab>c2 ghf5 ksj#_+wwl9' and output must be 'abc ghf ksjwwl'. How can I remove some extra characters within a text with SQL regex or other ways?

Answer 1

I don't know if this helps, but you can define a table with all characters / phrases you want to replace and do it like this:
DECLARE #CharsToReplace TABLE(SearchFor VARCHAR(100),ReplaceWith VARCHAR(100));
INSERT INTO #CharsToReplace VALUES('1',''),('2',''),('3',''),('4',''),('5',''),('6',''),('7',''),('8',''),('9',''),('0','');
DECLARE #YourString VARCHAR(100)='abc2 ghf5 ksjwwl9';
SELECT #YourString=REPLACE(#YourString,SearchFor,ReplaceWith)
FROM #CharsToReplace;
SELECT #YourString;
The result
abc ghf ksjwwl
If you'd define values in ReplaceWith this would work too.
UPDATE A function you can use in any select
Attention: This will be slow!
CREATE FUNCTION dbo.DeleteChars(#CharList NVARCHAR(MAX),#string NVARCHAR(MAX))
RETURNS NVARCHAR(MAX)
AS
BEGIN
DECLARE #List XML=(SELECT CAST('<x>'+ REPLACE(#CharList,',','</x><x>')+'</x>' AS XML));
SELECT #string=REPLACE(#string,ch.value(N'.',N'nvarchar(max)'),'')
FROM #List.nodes('/x') AS A(ch);
RETURN #string;
END
GO
--Test this with a mock-up table
DECLARE #SomeTable TABLE(SomeColumn VARCHAR(100));
INSERT INTO #SomeTable VALUES('abc2 ghf5 ksjwwl9'),('123 abc 456 hello');
--This is the char list (comma separated)
DECLARE #CharList VARCHAR(100)='1,2,3,4,5,6,7,8,9,0';
--This is how you call it
SELECT dbo.DeleteChars(#CharList,SomeColumn)
FROM #SomeTable
GO
--Clean up
DROP FUNCTION dbo.DeleteChars;
The result
abc ghf ksjwwl
abc hello