where clauses and selects

Hello,

Is it possible to perform a select in the where clause of a statement?

I have a situation where I've got one arm tied behind my back:  I can
only have a single table in the select and from clauses, but the where
clause appears to be freed from that restriction.

Given a statement as follows:

   SELECT foo.foo_id, foo.name
   FROM foo, bar
   WHERE foo.bar_id = bar.bar_id
   AND bar.name = 'martini';

I'm looking for a way to recast it so that the select and from clauses
refer to a single table and the join referencing the second table
occurs in the where clause.  For example, something like this:

   SELECT foo.foo_id, foo.name
   FROM foo
   WHERE (SELECT * FROM foo, bar WHERE ...)
   foo.bar_id = bar.bar_id
   AND bar.name = 'martini';

I've explored the "where exists" clause, but it's not supported by the
application toolkit I'm using. AFAIK, I've only got access to where ...

Thanks in advance!
Scott