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

number of papers published in ACL 2015
SELECT DISTINCT COUNT(DISTINCT paper.paperid) FROM paper, venue WHERE paper.year = 2015 AND venue.venueid = paper.venueid AND venue.venuename = 'ACL'
SELECT DISTINCT COUNT(DISTINCT "paper"."paperid") FROM "paper" JOIN "venue" ON "paper"."venueid" = "venue"."venueid" AND "venue"."venuename" = 'ACL' WHERE "paper"."year" = 2015