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

main topics of work by Brian DeRenzi
SELECT DISTINCT keyphrase.keyphrasename, SUM(paper.numcitedby) FROM author, keyphrase, paper, paperkeyphrase, writes WHERE author.authorname = 'Brian DeRenzi' AND paperkeyphrase.keyphraseid = keyphrase.keyphraseid AND paper.paperid = paperkeyphrase.paperid AND writes.authorid = author.authorid AND writes.paperid = paper.paperid GROUP BY keyphrase.keyphrasename ORDER BY SUM(paper.numcitedby) DESC
SELECT DISTINCT "keyphrase"."keyphrasename", SUM("paper"."numcitedby") FROM "author" JOIN "writes" ON "author"."authorid" = "writes"."authorid" JOIN "paper" ON "paper"."paperid" = "writes"."paperid" JOIN "paperkeyphrase" ON "paper"."paperid" = "paperkeyphrase"."paperid" JOIN "keyphrase" ON "keyphrase"."keyphraseid" = "paperkeyphrase"."keyphraseid" WHERE "author"."authorname" = 'Brian DeRenzi' GROUP BY "keyphrase"."keyphrasename" ORDER BY SUM("paper"."numcitedby") DESC NULLS LAST