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

What authors wrote papers about semantic parsing in 2016 ?
SELECT DISTINCT writes.authorid FROM author, keyphrase, paper, paperkeyphrase, writes WHERE keyphrase.keyphrasename = 'semantic parsing' AND paperkeyphrase.keyphraseid = keyphrase.keyphraseid AND paper.paperid = paperkeyphrase.paperid AND paper.year = 2016 AND writes.authorid = author.authorid AND writes.paperid = paper.paperid
SELECT DISTINCT "writes"."authorid" FROM "author" JOIN "writes" ON "author"."authorid" = "writes"."authorid" JOIN "paper" ON "paper"."paperid" = "writes"."paperid" AND "paper"."year" = 2016 JOIN "paperkeyphrase" ON "paper"."paperid" = "paperkeyphrase"."paperid" JOIN "keyphrase" ON "keyphrase"."keyphraseid" = "paperkeyphrase"."keyphraseid" AND "keyphrase"."keyphrasename" = 'semantic parsing'