OCS inventory on ubuntu server 16.04

Hi,

i have installed ocsinventory on ubuntu server 16.04 and then when i go to the web page of ocsreports i have this error :

ERROR: MySQL for PHP is not properly installed.
Try installing MySQL for php package (Debian: php5-mysql)

The problem is i can't install php5-mysql because ubuntu 16.04 have already the php7 so i can't override it and install php5 packages. is there any solution for that ?

thank you all