Remove whitespace before calling the function. Use SUBSTITUTE

If you uncomment this code it would return null:

--IF @encoded_text COLLATE LATIN1_GENERAL_BIN

-- LIKE '%[^ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=]%'

-- COLLATE LATIN1_GENERAL_BIN

-- RETURN NULL

try:

SET @encoded_text = SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(

@encoded_text, ' ',''),CHAR(9),''),CHAR(10),''),CHAR(13),'')

(Okay so 5 years for me to bother to check the discussion is a bit long. I use Oracle lately...)