just do it

SELECT * FROM gallery2 WHERE topic_id="939241" UNION SELECT * FROM gallery2 WHERE topic_id="1252940" UNION SELECT * FROM gallery2 WHERE topic_id="1435559" UNION SELECT * FROM gallery2 WHERE topic_id="1000818" UNION SELECT * FROM gallery2 WHERE topic_id="1111175" UNION SELECT * FROM gallery2 WHERE topic_id="42364" UNION SELECT * FROM gallery2 WHERE topic_id="543519" UNION SELECT * FROM gallery2 WHERE topic_id="1459123" UNION SELECT * FROM gallery2 WHERE topic_id="747193" UNION SELECT * FROM gallery2 WHERE topic_id="588748" UNION SELECT * FROM gallery2 WHERE topic_id="1066592" UNION SELECT * FROM gallery2 WHERE topic_id="1458013" UNION SELECT * FROM gallery2 WHERE topic_id="457165" UNION SELECT * FROM gallery2 WHERE topic_id="958059" UNION SELECT * FROM gallery2 WHERE topic_id="1456116" UNION SELECT * FROM gallery2 WHERE topic_id="603654"