CREATE EXTENSION twitter_fdw;
SELECT count(*) FROM twitter;
 count 
-------
     0
(1 row)

SELECT count(*) FROM twitter WHERE q = '#postgresql';
 count 
-------
    15
(1 row)

CREATE TEMP TABLE twtest (id int, from_user text);
INSERT INTO twtest(from_user)
	SELECT from_user FROM twitter WHERE q = '#postgres' LIMIT 1;
SELECT true FROM twtest INNER JOIN
	twitter USING(from_user) WHERE q = '#postgres';
 bool 
------
 t
(1 row)