I think I know where you would put it 😉

SELECT * FROM gallery2 WHERE topic_id="117420" UNION SELECT * FROM gallery2 WHERE topic_id="2539" UNION SELECT * FROM gallery2 WHERE topic_id="1187132" UNION SELECT * FROM gallery2 WHERE topic_id="984524" UNION SELECT * FROM gallery2 WHERE topic_id="340272" UNION SELECT * FROM gallery2 WHERE topic_id="1799629" UNION SELECT * FROM gallery2 WHERE topic_id="1742657" UNION SELECT * FROM gallery2 WHERE topic_id="622594" UNION SELECT * FROM gallery2 WHERE topic_id="1769836" UNION SELECT * FROM gallery2 WHERE topic_id="1177376" UNION SELECT * FROM gallery2 WHERE topic_id="66078" UNION SELECT * FROM gallery2 WHERE topic_id="1808999" UNION SELECT * FROM gallery2 WHERE topic_id="1019725" UNION SELECT * FROM gallery2 WHERE topic_id="495628" UNION SELECT * FROM gallery2 WHERE topic_id="454435" UNION SELECT * FROM gallery2 WHERE topic_id="1703221"