Hi Paulo,
The tables that need to be linked together to view the results are: survey, survey_answer, and survey_question.
The survey table will give you the object_type and object_id in which you can relate back to the persid of a ticket from which a survey was completed.
The survey_answer table is the available answer values, NOT the actual results of the survey.
The survey_question table stores the response and any comments.
Thanks,
Scott