SELECT * FROM copang_main.member WHERE age >= 27; -> 27세 이상인 사람 모두 검색 SELECT * FROM copang_main.member WHERE age BETWEEN 30 AND 39; -> 30대인 사람 모두 검색 SELECT * FROM copang_main.member WHERE sign_up_day > '2019-01-01'; -> 가입 날짜가 2019-01-01 이후 검색 SELECT * FROM copang_main.member WHERE sign_up_day BETWEEN '2018-01-01' AND '2018-12-31'; -> 가입날짜가 2018-01-01 ~ 2018-12-31인 사람
