Unable to replace Char(63) by SQL query - sql

Question

I am having some rows in table with some unusual character. When I use ascii() or unicode() for that character, it returns 63. But when I try this -
update MyTable
set MyColumn = replace(MyColumn,char(63),'')
it does not replace. The unusual character still exists after the replace function. Char(63) incidentally looks like a question mark.
For example my string is 'ddd#dd ddd' where # it's my unusual character and
select unicode('#')
return me 63.But this code
declare #str nvarchar(10) = 'ddd#dd ddd'
set #char = char(unicode('#'))
set #str = replace(#str,#char,'')
is working!
Any ideas how to resolve this?
Additional information:
select ascii('�') returns 63, and so does select ascii('?'). Finally select char(63) returns ? and not the diamond-question-mark.
When this character is pasted into Excel or a text editor, it looks like a space, but in an SQL Server Query window (and, apparently, here on StackOverflow as well), it looks like a diamond containing a question mark.

Answer 1

Not only does char(63) look like a '?', it is actually a '?'.
(As a simple test ensure you have numlock on your keyboard on, hold down the alt key andtype '63' into the number pad - you can all sorts of fun this way, try alt-205, then alt-206 and alt-205 again: ═╬═)
Its possible that the '?' you are seeing isn't a char(63) however, and more indicitive of a character that SQL Server doesn't know how to display.
What do you get when you run:
select ascii(substring('[yourstring]',[pos],1));
--or
select unicode(substring('[yourstring]',[pos],1));
Where [yourstring] is your string and [pos] is the position of your char in the string
EDIT
From your comment it seems like it is a question mark. Have you tried:
replace(MyColumn,'?','')
EDIT2
Out of interest, what does the following do for you:
replace(replace(MyColumn,char(146),''),char(63),'')

Answer 2

char(63) is a question mark. It sounds like these "unusual" characters are displayed as a question mark, but are not actually characters with char code 63.
If this is the case, then removing occurrences of char(63) (aka '?') will of course have no effect on these "unusual" characters.

Answer 3

I believe you actually didn't have issues with literally CHAR(63), because that should be just a normal character and you should be able to properly work with it.
What I think happened is that, by mistake, an UTF character (for example, a cyrilic "А") was inserted into the table - and either your:
columns setup,
the SQL code,
or the passed in parameters
were not prepared for that.
In this case, the sign might be visible to you as ?, and its CHAR() function would actually give 63, but you should really use the NCHAR() to figure out the real code of it.
Let me give a specific example, that I had multiple times - issues
with that Cyrilic "А", which looks identical to the Latin one, but has
a unicode of 1040.
If you try to use the non-UTF CHAR function on that 1040 character,
you would get a code 63, which is not true (and is probably just an
info about the first byte of multibyte character).
Actually, run this to make the differences in my example obvious:
SELECT NCHAR(65) AS Latin_A, NCHAR(1040) Cyrilic_A, ASCII(NCHAR(1040)) Latin_A_Code, UNICODE(NCHAR(1040)) Cyrilic_A_Code;

Answer 4

That empty string Which shows us '?' in substring.
Gives us Ascii value as 63.
It's a Zero Width space which gets appended if you copy data from ui and insert into the database.
To replace the data, you can use below query
**set MyColumn = replace(MyColumn,NCHAR(8203),'')**

Answer 5

It's an older question, but I've run into this problem as well. I found the solution somewhere else on internet, but I thought it would be good to share it here as well. Have a good day.
Replace(YourString, nchar(65533) COLLATE Latin1_General_BIN2, '')

Answer 6

This should work as well:
UPDATE TABLE
SET [FieldName] = SUBSTRING([FieldName], 2, LEN([FieldName]))
WHERE ASCII([FieldName]) = 63