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

datasets in knn papers
SELECT DISTINCT dataset.datasetid FROM dataset, keyphrase, paperdataset, paperkeyphrase WHERE keyphrase.keyphrasename = 'knn' AND paperdataset.datasetid = dataset.datasetid AND paperkeyphrase.keyphraseid = keyphrase.keyphraseid AND paperkeyphrase.paperid = paperdataset.paperid
SELECT DISTINCT "dataset"."datasetid" FROM "dataset" JOIN "paperdataset" ON "dataset"."datasetid" = "paperdataset"."datasetid" JOIN "paperkeyphrase" ON "paperdataset"."paperid" = "paperkeyphrase"."paperid" JOIN "keyphrase" ON "keyphrase"."keyphraseid" = "paperkeyphrase"."keyphraseid" AND "keyphrase"."keyphrasename" = 'knn'