From your Q 'Session doesn't exist joomla' posted on SO, I can see in your comment "in phpmyadmin, only some tables displayed. But in mysql/data folder all tables exist" that obviously process "I have copied my project and its database to wamp server." somehow went wrong.
For transfering Joomla site correctly I would recommend using leading Joomla extension Akeeba Backup. Install free Core version on source site, and follow documentation to create installable archive, which will have all it's files and database(s). That archive you will then unpack in the root folder of destination site, go to it's URL in browser, complete Mini-Installation process which will correctly upload database(s) to new location and create correct configuration file for the new site, thus creating exact copy of source site.
I have been using this extension since 2007 and Joomla 1.0, when it was still
called JoomlaPack. Also, searching JSE for 'akeeba' will yield bunch of questions, answers and comments regrading this must-have J! Ext.