Expressing some queries without employing JOIN or OUTER JOIN Assume the following relations schemas:


S(A,B)
T(B,C)


Rewrite the following expressions without using join or outer join operators explicitly:


S LEFT OUTER JOIN T
S FULL OUTER JOIN T


How do I do these two questions? I've tried using a where clause but I don't think it is correct. I know the first one has to use a union but how do I go about writing the queries?
Left outer join will be:

select s.a, s.b, (select c from t where s.b =t.b) as outercol
from s


Full outer join will be:

select s.a, s.b, (select c from t where s.b =t.b) as outercol
from s
union all
select null, b, c from t
where b not in (select b from s)