DROP TABLE tmp;
DROP TABLE tmp2;

CREATE TABLE tmp AS SELECT DISTINCT trans_id FROM acc_trans WHERE chart_id IN (SELECT fldvalue::integer FROM defaults WHERE fldname='fxgain_accno_id');

CREATE TABLE tmp2 AS SELECT trans_id FROM tmp WHERE trans_id IN (SELECT DISTINCT trans_id FROM acc_trans WHERE chart_id IN (SELECT fldvalue::integer FROM defaults WHERE fldname='fxloss_accno_id'));

SELECT invnumber FROM ar WHERE id IN (SELECT trans_id FROM tmp2);
SELECT invnumber FROM ap WHERE id IN (SELECT trans_id FROM tmp2);