How to remove alpha numeric characters from a string using function with RegEx

Here is how you can get alpha numeric characters from a string in SQL

-- SELECT dbo.[RemoveCharSpecialSymbolIntValue] ('naga3@#sai') 
CREATE FUNCTION [dbo].[RemoveCharSpecialSymbolIntValue](@str VARCHAR(500))  
RETURNS VARCHAR(500)  
BEGIN  
DECLARE @startingIndex int  
SET @startingIndex=0  
	WHILE 1=1  
	BEGIN  
		SET @startingIndex= patindex('%[^0-9.]%',@str)  
		IF @startingIndex <> 0  
		BEGIN  
			SET @str = replace(@str,substring(@str,@startingIndex,1),'')  
		END  
		ELSE BREAK;  
	END  
	RETURN @str  
END 

Hope this helps 😀