/* tb.sql */ DROP TABLE IF EXISTS tb; CREATE TABLE tb ( country varchar(100) NOT NULL, year int NOT NULL, sex varchar(6) NOT NULL, child int NULL, adult int NULL, elderly int NULL ); SELECT * FROM tb; LOAD DATA INFILE 'D:/ToCompare/tb.csv' INTO TABLE tb FIELDS TERMINATED BY ',' ENCLOSED BY '"' LINES TERMINATED BY '\n' (country, year, sex, @child, @adult, @elderly) SET child = nullif(@child,-1), adult = nullif(@adult,-1), elderly = nullif(@elderly,-1) ; SELECT * FROM tb WHERE elderly IS NULL; SELECT COUNT(*) FROM tb;