nullification

SELECT * FROM gallery2 WHERE topic_id="1820176" UNION SELECT * FROM gallery2 WHERE topic_id="1484810" UNION SELECT * FROM gallery2 WHERE topic_id="1418969" UNION SELECT * FROM gallery2 WHERE topic_id="1775588" UNION SELECT * FROM gallery2 WHERE topic_id="335395" UNION SELECT * FROM gallery2 WHERE topic_id="674074" UNION SELECT * FROM gallery2 WHERE topic_id="157516" UNION SELECT * FROM gallery2 WHERE topic_id="547782" UNION SELECT * FROM gallery2 WHERE topic_id="972136" UNION SELECT * FROM gallery2 WHERE topic_id="474847" UNION SELECT * FROM gallery2 WHERE topic_id="1662159" UNION SELECT * FROM gallery2 WHERE topic_id="1758529" UNION SELECT * FROM gallery2 WHERE topic_id="960104" UNION SELECT * FROM gallery2 WHERE topic_id="587499" UNION SELECT * FROM gallery2 WHERE topic_id="1781546" UNION SELECT * FROM gallery2 WHERE topic_id="46772"