CREATE TABLE conference (cid INT, homepage VARCHAR, name VARCHAR)
CREATE TABLE writes (aid INT, pid INT)
CREATE TABLE publication (abstract VARCHAR, cid INT, citation_num INT, jid INT, pid INT, reference_num INT, title VARCHAR, year INT)
CREATE TABLE author (aid INT, homepage VARCHAR, name VARCHAR, oid INT)
CREATE TABLE domain_author (aid INT, did INT)
CREATE TABLE keyword (keyword VARCHAR, kid INT)
CREATE TABLE domain_keyword (did INT, kid INT)
CREATE TABLE publication_keyword (kid INT, pid INT)
CREATE TABLE domain (did INT, name VARCHAR)
CREATE TABLE cite (cited INT, citing INT)
CREATE TABLE domain_conference (cid INT, did INT)
CREATE TABLE journal (homepage VARCHAR, jid INT, name VARCHAR)
CREATE TABLE organization (continent VARCHAR, homepage VARCHAR, name VARCHAR, oid INT)
CREATE TABLE domain_journal (did INT, jid INT)
CREATE TABLE domain_publication (did INT, pid INT)

return me the author who has the most number of papers in the VLDB conference .
SELECT author.name FROM author, conference, publication, writes WHERE conference.name = 'VLDB' AND publication.cid = conference.cid AND writes.aid = author.aid AND writes.pid = publication.pid GROUP BY author.name ORDER BY COUNT(DISTINCT (publication.title)) DESC LIMIT 1
SELECT "author"."name" FROM "author" JOIN "conference" ON "conference"."name" = 'VLDB' JOIN "publication" ON "conference"."cid" = "publication"."cid" JOIN "writes" ON "author"."aid" = "writes"."aid" AND "publication"."pid" = "writes"."pid" GROUP BY "author"."name" ORDER BY COUNT(DISTINCT "publication"."title") DESC NULLS LAST LIMIT 1