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

what topics does oren etzioni write about most ?
SELECT DISTINCT COUNT(paperkeyphrase.keyphraseid), paperkeyphrase.keyphraseid FROM author, paper, paperkeyphrase, writes WHERE author.authorname = 'oren etzioni' AND paper.paperid = paperkeyphrase.paperid AND writes.authorid = author.authorid AND writes.paperid = paper.paperid GROUP BY paperkeyphrase.keyphraseid ORDER BY COUNT(paperkeyphrase.keyphraseid) DESC
SELECT DISTINCT COUNT("paperkeyphrase"."keyphraseid"), "paperkeyphrase"."keyphraseid" FROM "author" JOIN "writes" ON "author"."authorid" = "writes"."authorid" JOIN "paper" ON "paper"."paperid" = "writes"."paperid" JOIN "paperkeyphrase" ON "paper"."paperid" = "paperkeyphrase"."paperid" WHERE "author"."authorname" = 'oren etzioni' GROUP BY "paperkeyphrase"."keyphraseid" ORDER BY COUNT("paperkeyphrase"."keyphraseid") DESC