CREATE TABLE journal (journalid NUMBER, journalname VARCHAR2)
CREATE TABLE author (authorid NUMBER, authorname VARCHAR2)
CREATE TABLE paperdataset (paperid NUMBER, datasetid NUMBER)
CREATE TABLE paperkeyphrase (paperid NUMBER, keyphraseid NUMBER)
CREATE TABLE field (fieldid NUMBER)
CREATE TABLE keyphrase (keyphraseid NUMBER, keyphrasename VARCHAR2)
CREATE TABLE dataset (datasetid NUMBER, datasetname VARCHAR2)
CREATE TABLE cite (citingpaperid NUMBER, citedpaperid NUMBER)
CREATE TABLE venue (venueid NUMBER, venuename VARCHAR2)
CREATE TABLE writes (paperid NUMBER, authorid NUMBER)
CREATE TABLE paperfield (fieldid NUMBER, paperid NUMBER)
CREATE TABLE paper (paperid NUMBER, title VARCHAR2, venueid NUMBER, year NUMBER, numciting NUMBER, numcitedby NUMBER, journalid NUMBER)

who published the most papers in ACL 2010
SELECT DISTINCT COUNT(paper.paperid), writes.authorid FROM paper, venue, writes WHERE paper.year = 2010 AND venue.venueid = paper.venueid AND venue.venuename = 'ACL' AND writes.paperid = paper.paperid GROUP BY writes.authorid ORDER BY COUNT(paper.paperid) DESC
SELECT DISTINCT COUNT("paper"."paperid"), "writes"."authorid" FROM "paper" JOIN "venue" ON "paper"."venueid" = "venue"."venueid" AND "venue"."venuename" = 'ACL' JOIN "writes" ON "paper"."paperid" = "writes"."paperid" WHERE "paper"."year" = 2010 GROUP BY "writes"."authorid" ORDER BY COUNT("paper"."paperid") DESC