I mean exactly what I say:
The `message_has_been_sent` has been update, while `ml_message` isn't updated.
In addition:

Does the SQL statement work when you paste it into the mysql client?

yes

Does your program connect to the right database?

yes

You talk about columns message_has_been_sent and message_send in your statement, but your prose mentions columns message_has_been_sent and ml_message. Which is it?

It is a paste and copy error from my side.
I correct it immediatly.

Why are you sure that message_has_been_sent gets updated? Are you sure it didn't have the same value before you tested?

yes.
because before the value was different.
I think it is a DBI driver error in the fileds with small values (tinyint, smallint, mediumint, and enum('Y','N'), because with mysql client all works fine, and with the same code with PHP all works fine.