CREATE TABLE conference (cid NUMBER, homepage VARCHAR2, name VARCHAR2)
CREATE TABLE writes (aid NUMBER, pid NUMBER)
CREATE TABLE publication (abstract VARCHAR2, cid NUMBER, citation_num NUMBER, jid NUMBER, pid NUMBER, reference_num NUMBER, title VARCHAR2, year NUMBER)
CREATE TABLE author (aid NUMBER, homepage VARCHAR2, name VARCHAR2, oid NUMBER)
CREATE TABLE domain_author (aid NUMBER, did NUMBER)
CREATE TABLE keyword (keyword VARCHAR2, kid NUMBER)
CREATE TABLE domain_keyword (did NUMBER, kid NUMBER)
CREATE TABLE publication_keyword (kid NUMBER, pid NUMBER)
CREATE TABLE domain (did NUMBER, name VARCHAR2)
CREATE TABLE cite (cited NUMBER, citing NUMBER)
CREATE TABLE domain_conference (cid NUMBER, did NUMBER)
CREATE TABLE journal (homepage VARCHAR2, jid NUMBER, name VARCHAR2)
CREATE TABLE organization (continent VARCHAR2, homepage VARCHAR2, name VARCHAR2, oid NUMBER)
CREATE TABLE domain_journal (did NUMBER, jid NUMBER)
CREATE TABLE domain_publication (did NUMBER, pid NUMBER)

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 FETCH FIRST 1 ROWS ONLY