Can an UPDATE clause in MYSQL using PHP update multiple records in a single query?

Ok, I have this message table with values ​​like these:

msg_id  recipient_id   read   locked   new
  0         1            N       Y      Y
  2         1            Y       N      N

      

        
        
        
      

    

ok so let's just say this is a message table and I want to reset all messages addressed to the recipient with id = 1

I was wondering why

UPDATE `messages` SET `new`='Y',`read`='N',`locked`='N' where `recipient_id`=1;

      

        
        
        
      

    

doesn't work, MYSQL always returns 0 affected rows ... can anyone help me?

for robert gamble: yes i'm pretty sure the values ​​have changed since my goal for this update request is to reset the data i used for the testing steps: D