Join-Question

Hi,

I have a problem retrieving information from serveral 
different tables.

For example:

I have three tables:

Table 1 contains that person X has the hobby nr. 1, person 2 has 
hobby nr 42 etc (fields: person_id, hobby_nr)
Table 2: Hobby nr 1 is "soccer", hobby nr 2 is "jazz" (fields: 
hobby_nr, hobby_text) Table 3 contains the  first and last name for 
the persons in table nr 1 (fields person_id, first_name, last_name).

Now I want to find out for example the following:

If someone looks for a hobby, find out the first and last name of 
those who like hobby nr 1. If someone does not look for hobby, just 
print out all the names in the database.

In MySQL I would do something like a LEFT JOIN, wouldn´t I? But in 
Postgres I could not find anything about left or right joins. Any 
idea how to solve this problem??

Thanx so much for your help
Dorthe