Need to change some entries in column to NULL

I have just started updating a website that I setup with an earlier version of WA extensions. Changing it over to mysqli at the same time.

I found a few things in the actual db that I need to change. I have a phone2 field that for some has 3 different values in it. NULL which is NOW the default (it was   for some reason. Did it 7 or 8 years ago so dont know why. The other values are   and then a bunch with actual phone numbers.

I have searched online and have succeeded on messing up the table ( dropped and restored already) for a way to change the   to NULL. I dont want to change the ones with actual phone numbers. I managed to set it ALL to NULL which is when I restored a backup.

Here is one I tried that obviously didnt work..
UPDATE alumni SET phone2 = NULL WHERE phone2 = ' ';

Hoping I can get a little guidance. I am beginning to think it isn't possible. can this be done? There are 96 rows to do. I will do manually if I have to but would prefer not to..
Thanks.

Your sample update statement should work. What was the result when you tried?

Ok.. My bad.. Got that to work. I was running the 'simulate query' when it gave the error.. Actually running it succeeded.

Got rid of the   .. Found another character I need to get rid of. It is the  character. Doing some searching it seems to have something to do with the collation. It is set as latin1_swedish_ci . Should I change that to a different collation and will that mess up the db by doing so.

If I do the same UPDATE with that character (Â) it does not find it so I cant get rid of it.

If you change it to utf8 it should help. Then copy the character from one of the fields and paste it into the update query and it should find it. That is a garbage character that could actually be several characters, so you may have to copy it more than once.

Sounds. great.. Thanks Ray!!

Got it switched to UTF-8. Copied and pasted that character into the sql and it does not find anything. Found there are over 200 of them by just looking...

What SQL statement are you using to find and replace the character?

in phpmyadmin going into one of the records that has it and copy it from there.
UPDATE * FROM `alumni` SET `phone2` = NULL WHERE `phone2` = 'Â '; did it with and without the space after. Thats what the paste did, with the space.
Tried it with Select also just to view it.. nata..
Its not that big of a deal. I can manually delete them although learning what is going on would be nice.
Thanks.

Is that the full value of the field with the space? I'd have to play around with it, but there is probably another hidden character before or after that is causing the match to not work.

Have you tried:
SELECT * FROM `alumni` SET `phone2` = NULL WHERE `phone2` LIKE '%Â%'

Very strange result.
I am able to do a SELECT * FROM 'alumni' WHERE 'phone2' LIKE '%Â %'; and it finds 414 entries.
Try the update statement you just gave me and it fails. No specifics. Just that line.

Should just be:
UPDATE `alumni` SET `phone2` = NULL WHERE `phone2` LIKE '%Â%'