Is it possible to get multiple values from a subquery?

A Subquery in the Select clause, as in your case, is also known as a Scalar Subquery, which means that it's a form of expression. Meaning that it can only return one value.

I'm afraid you can't return multiple columns from a single Scalar Subquery, no.

Here's more about Oracle Scalar Subqueries:

http://docs.oracle.com/cd/B19306_01/server.102/b14200/expressions010.htm#i1033549

Here are two methods to get more than 1 column in a scalar subquery (or inline subquery) and querying the lookup table only once. This is a bit convoluted but can be the very efficient in some special cases.

1. You can use concatenation to get several columns at once:

   SELECT x, 
          regexp_substr(yz, '[^^]+', 1, 1) y,
          regexp_substr(yz, '[^^]+', 1, 2) z
     FROM (SELECT a.x,
                  (SELECT b.y || '^' || b.z yz
                     FROM b
                    WHERE b.v = a.v)
                     yz
             FROM a)
   

   You would need to make sure that no column in the list contain the separator character.

2. You could also use SQL objects:

   CREATE OR REPLACE TYPE b_obj AS OBJECT (y number, z number);
   
   SELECT x, 
          v.yz.y y,
          v.yz.z z
     FROM (SELECT a.x,
                  (SELECT b_obj(y, z) yz
                     FROM b
                    WHERE b.v = a.v)
                     yz
             FROM a) v
   

It's incorrect, but you can try this instead:

select
    a.x,
    ( select b.y from b where b.v = a.v) as by,
    ( select b.z from b where b.v = a.v) as bz
from a

you can also use subquery in join

 select
        a.x,
        b.y,
        b.z
    from a
    left join (select y,z from b where ... ) b on b.v = a.v

or

   select
        a.x,
        b.y,
        b.z
    from a
    left join b on b.v = a.v

Can't you use JOIN like this one?

SELECT
a.x , b.y, b.z 
FROM a 
LEFT OUTER JOIN b ON b.v = a.v

(I don't know Oracle Syntax. So I wrote SQL syntax)