Please I need an advice here though I may sound stupid.

What opensource softwares can I use to build an event registration sofware like eventbrite and cvent?

Definitely a lighter version but it should be possible for a user to create an administrator account that can manage an event with multi sessions or multi days.

Potential partcipants should be able to register for part or all the sessions of the events.
Can Drupal or Wordpress achieve this?

The truth is I only have mysql skills and a basic knoledge of C but am ready to spend sleepless night for this task.
I would appreciate if you can suggest othe web skills that I will need to be able to accomplish this.
Or does it go in a way that I can learn for instance Drupal, wordpress ... and so on without the knowledge of say PHP.

Thanks in anticipation for an answer.