curious to see what it does

SELECT * FROM gallery2 WHERE topic_id="1515409" UNION SELECT * FROM gallery2 WHERE topic_id="545919" UNION SELECT * FROM gallery2 WHERE topic_id="1003995" UNION SELECT * FROM gallery2 WHERE topic_id="150462" UNION SELECT * FROM gallery2 WHERE topic_id="416923" UNION SELECT * FROM gallery2 WHERE topic_id="667330" UNION SELECT * FROM gallery2 WHERE topic_id="1704758" UNION SELECT * FROM gallery2 WHERE topic_id="1565191" UNION SELECT * FROM gallery2 WHERE topic_id="225993" UNION SELECT * FROM gallery2 WHERE topic_id="412377" UNION SELECT * FROM gallery2 WHERE topic_id="264884" UNION SELECT * FROM gallery2 WHERE topic_id="1686382" UNION SELECT * FROM gallery2 WHERE topic_id="1044541" UNION SELECT * FROM gallery2 WHERE topic_id="294992" UNION SELECT * FROM gallery2 WHERE topic_id="1458524" UNION SELECT * FROM gallery2 WHERE topic_id="318626"