The upgrade to Ubuntu 12.04 delete MySQL and I need urgently to get it back. The problem is that I'm getting an error installing it, either with apt-get or aptitude:

Errors were encountered while processing:

 /var/cache/apt/archives/mysql-server-5.5_5.5.22-0ubuntu1_amd64.deb

E: Sub-process /usr/bin/dpkg returned an error code (1)

I've already tried different ways to install MySQL but without success, as reported in this thread at the Forum:

http://ubuntuforums.org/showthread.php?t=1998260

I believe I should file a bug, but following the instructions I thought better to ask here first.

Thank you for reading.