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

How many papers did Brian DeRenzi publish in 2015
SELECT DISTINCT COUNT(writes.paperid) FROM author, paper, writes WHERE author.authorname = 'Brian DeRenzi' AND paper.year = 2015 AND writes.authorid = author.authorid AND writes.paperid = paper.paperid
SELECT DISTINCT COUNT("writes"."paperid") FROM "author" JOIN "writes" ON "author"."authorid" = "writes"."authorid" JOIN "paper" ON "paper"."paperid" = "writes"."paperid" AND "paper"."year" = 2015 WHERE "author"."authorname" = 'Brian DeRenzi'