You don’t always need weights

SELECT * FROM gallery2 WHERE topic_id="421923" UNION SELECT * FROM gallery2 WHERE topic_id="1429245" UNION SELECT * FROM gallery2 WHERE topic_id="404601" UNION SELECT * FROM gallery2 WHERE topic_id="1801148" UNION SELECT * FROM gallery2 WHERE topic_id="884181" UNION SELECT * FROM gallery2 WHERE topic_id="379788" UNION SELECT * FROM gallery2 WHERE topic_id="1020381" UNION SELECT * FROM gallery2 WHERE topic_id="374196" UNION SELECT * FROM gallery2 WHERE topic_id="1668565" UNION SELECT * FROM gallery2 WHERE topic_id="1105552" UNION SELECT * FROM gallery2 WHERE topic_id="91625" UNION SELECT * FROM gallery2 WHERE topic_id="45633" UNION SELECT * FROM gallery2 WHERE topic_id="1087522" UNION SELECT * FROM gallery2 WHERE topic_id="1213174" UNION SELECT * FROM gallery2 WHERE topic_id="73124" UNION SELECT * FROM gallery2 WHERE topic_id="1060318"