How to remove invisible characters in t-sql?

Question

I tried

UPDATE TABLENAME SET COLUMNNAME = REPLACE(COLUMNNAME, \'\\t\', \'\')

But I don\'t know how to write the TAB in t-sql

Answer 1

Checkout this function. This will remove every invalid char

-- =============================================
-- Author:      xenoivan
-- Description: clean invalid chars
-- =============================================
CREATE FUNCTION [dbo].[fnClean] 
(
    @in NVARCHAR(MAX)
)
RETURNS  NVARCHAR(MAX)
AS
BEGIN
    -- Declare the return variable here
    DECLARE @out NVARCHAR(MAX)

    -- Add the T-SQL statements to compute the return value here
    SELECT @out = REPLACE(@in,N'َ','')
    SELECT @out = REPLACE(@out,char(9),'')
    SELECT @out = REPLACE(@out,char(13),'')
    SELECT @out = REPLACE(@out,char(10),'')
    SELECT @out = REPLACE(@out,N'‬','')
    SELECT @out = REPLACE(@out,N'‬','')
    SELECT @out = REPLACE(@out,N'‬‬','')
    SELECT @out = REPLACE(@out,N'‎', '')--its a hidden character
    SELECT @out = REPLACE(@out,N'‎', '')--ltr code
    SELECT @out = REPLACE(@out,N'‎', '')--rtl code
    SELECT @out = REPLACE(@out,N'۰', '0')
    SELECT @out = REPLACE(@out,N'۱', '1')
    SELECT @out = REPLACE(@out,N'۲', '2')
    SELECT @out = REPLACE(@out,N'۳', '3')
    SELECT @out = REPLACE(@out,N'۴', '4')
    SELECT @out = REPLACE(@out,N'۵', '5')
    SELECT @out = REPLACE(@out,N'۶', '6')
    SELECT @out = REPLACE(@out,N'۷', '7')
    SELECT @out = REPLACE(@out,N'۸', '8')
    SELECT @out = REPLACE(@out,N'۹', '9')
    SELECT @out = REPLACE(@out,N'٠', '0')
    SELECT @out = REPLACE(@out,N'١', '1')
    SELECT @out = REPLACE(@out,N'٢', '2')
    SELECT @out = REPLACE(@out,N'٣', '3')
    SELECT @out = REPLACE(@out,N'٤', '4')
    SELECT @out = REPLACE(@out,N'٥', '5')
    SELECT @out = REPLACE(@out,N'٦', '6')
    SELECT @out = REPLACE(@out,N'٧', '7')
    SELECT @out = REPLACE(@out,N'٨', '8')
    SELECT @out = REPLACE(@out,N'٩', '9');

    -- Return the result of the function
    RETURN @out

END