instruction: keyphrases used by Dan Suciu
response: SELECT DISTINCT keyphrase.keyphraseid FROM author, keyphrase, paper, paperkeyphrase, writes WHERE author.authorname = 'Dan Suciu' AND paperkeyphrase.keyphraseid = keyphrase.keyphraseid AND paper.paperid = paperkeyphrase.paperid AND writes.authorid = author.authorid AND writes.paperid = paper.paperid