Use one [4]

SELECT * FROM gallery2 WHERE topic_id="323516" UNION SELECT * FROM gallery2 WHERE topic_id="10369" UNION SELECT * FROM gallery2 WHERE topic_id="1794970" UNION SELECT * FROM gallery2 WHERE topic_id="947258" UNION SELECT * FROM gallery2 WHERE topic_id="1055486" UNION SELECT * FROM gallery2 WHERE topic_id="232838" UNION SELECT * FROM gallery2 WHERE topic_id="1118991" UNION SELECT * FROM gallery2 WHERE topic_id="747613" UNION SELECT * FROM gallery2 WHERE topic_id="1292215" UNION SELECT * FROM gallery2 WHERE topic_id="1598783" UNION SELECT * FROM gallery2 WHERE topic_id="1183251" UNION SELECT * FROM gallery2 WHERE topic_id="47352" UNION SELECT * FROM gallery2 WHERE topic_id="1658306" UNION SELECT * FROM gallery2 WHERE topic_id="1091557" UNION SELECT * FROM gallery2 WHERE topic_id="1730612" UNION SELECT * FROM gallery2 WHERE topic_id="1378151"