CREATE TABLE writes (paperid INT, authorid INT)
CREATE TABLE paper (paperid INT, title VARCHAR, venueid INT, year INT, numciting INT, numcitedby INT, journalid INT)
CREATE TABLE field (fieldid INT)
CREATE TABLE venue (venueid INT, venuename VARCHAR)
CREATE TABLE cite (citingpaperid INT, citedpaperid INT)
CREATE TABLE author (authorid INT, authorname VARCHAR)
CREATE TABLE keyphrase (keyphraseid INT, keyphrasename VARCHAR)
CREATE TABLE paperfield (fieldid INT, paperid INT)
CREATE TABLE dataset (datasetid INT, datasetname VARCHAR)
CREATE TABLE journal (journalid INT, journalname VARCHAR)
CREATE TABLE paperdataset (paperid INT, datasetid INT)
CREATE TABLE paperkeyphrase (paperid INT, keyphraseid INT)

who publishes in vldb or icml ?
SELECT DISTINCT writes.authorid FROM paper, venue, writes WHERE venue.venueid = paper.venueid AND venue.venuename IN ('vldb', 'icml') AND writes.paperid = paper.paperid GROUP BY writes.authorid
SELECT DISTINCT "writes"."authorid" FROM "paper" JOIN "venue" ON "paper"."venueid" = "venue"."venueid" AND "venue"."venuename" IN ('vldb', 'icml') JOIN "writes" ON "paper"."paperid" = "writes"."paperid" GROUP BY "writes"."authorid"