How do I remove extended ASCII characters from a string in T-SQL?

Question

I need to filter out (remove) extended ASCII characters from a SELECT statement in T-SQL.

I\'m using a stored procedure to do so.

Expected input:

<         


        

Answer 1

The solution provided by amit kohan works, but was to slow for me. With large string data, the iteration trough each character is not optimal. I've made the following function, with isn't very compact but fast.

CREATE FUNCTIONdbo.F_StripLowAscii
(
   @Name nvarchar(max)
)
RETURN nvarchar(max) as
BEGIN
DECLARE @Result nvarchar(max) 

    If @Name IS NULL 
      RETURN @Name 

    DECLARE @BlankRange VARCHAR(15) 
    DECLARE @FoundAt INTEGER 

    -- ASCII CHAR #0 needs a special treatment
    SET @BlankRange = '%[' + CHAR(0) + ']%' 
    SET @FoundAt = PATINDEX(@BlankRange ,@Name COLLATE SQL_Latin1_General_CP850_Bin) 
    WHILE @FoundAt > 0 
    BEGIN 
        SET @name = left(@name, @FoundAt-1 ) + SUBSTRING(@name, @FoundAt+1, LEN(@Name))
        SET @FoundAt = PATINDEX(@BlankRange ,@Name COLLATE SQL_Latin1_General_CP850_Bin) 
    END 


    SET @BlankRange = '%[' + CHAR(1)+'-'+CHAR(8) + ']%' 
    SET @FoundAt = PATINDEX(@BlankRange ,@Name COLLATE SQL_Latin1_General_CP850_Bin) 
    WHILE @FoundAt > 0 
    BEGIN 
        SET @name = Replace(@Name, SUBSTRING(@Name, @FoundAt,1),'')
        SET @FoundAt = PATINDEX(@BlankRange ,@Name COLLATE SQL_Latin1_General_CP850_Bin) 
    END 

    SET @BlankRange = '%[' + CHAR(11)+'-'+CHAR(12) + ']%' 
    SET @FoundAt = PATINDEX(@BlankRange ,@Name COLLATE SQL_Latin1_General_CP850_Bin) 
    WHILE @FoundAt > 0 
    BEGIN 
        SET @name = Replace(@Name, SUBSTRING(@Name, @FoundAt,1),'')
        SET @FoundAt = PATINDEX(@BlankRange ,@Name COLLATE SQL_Latin1_General_CP850_Bin) 
    END 

    SET @BlankRange = '%[' + CHAR(14)+'-'+CHAR(31) + ']%' 
    SET @FoundAt = PATINDEX(@BlankRange ,@Name COLLATE SQL_Latin1_General_CP850_Bin) 
    WHILE @FoundAt > 0 
    BEGIN 
        SET @name = Replace(@Name, SUBSTRING(@Name, @FoundAt,1),'')
        SET @FoundAt = PATINDEX(@BlankRange ,@Name COLLATE SQL_Latin1_General_CP850_Bin) 
    END 

    RETURN @Name 

END
GO