psql question

Hi,

The following 'SELECT' query fails in psql, but it works
in Oracle sqlplus ...

  mydb=# create table emp
  mydb-# (firstname varchar(255),lastname varchar(255),empno int);
  CREATE
  mydb=# insert into emp (firstname,lastname,empno) values ('John','Doe',1234);

  INSERT 44968 1
  mydb=# select empno from emp where ((firstname,lastname) IN
  mydb-# (('John','Doe'),('Joe','Blow')));
  ERROR:  parser: parse error at or near "'"
  ERROR:  parser: parse error at or near "'"

Whereas in sqlplus:

  SQL> select empno from emp where ((firstname,lastname) IN
    2  (('John','Doe'),('Joe','Blow')));

       EMPNO
  ----------
        1234

Can anyone tell me what syntax _will_ work in psql?

Many thx,
Mark