excluding rows

[esmedia]

hi all,
i came up with this problem:

i have 3 tables:

create table questions (id ...);
create table users (id ...);
create table answers (question_id ..., user_id ...);

answers

contains all users' answers given to the questions (questions can be answered more than once by different users). i now want to select all questions which were ...

1) not answered at all
plus!:
2) not answered by a certain user

i'm too new to sql to find a solution (without subselects - because i have to use mysql here)

tia!
dieter [sig][/sig]

 

[esmedia]

sorry - it should read:

... 2) already answered by a certain user [sig][/sig]