SQL 문법(2)

SELECT * FROM orders o

SELECT user_id, email, course_id, course_title FROM orders o

★ 중복값 제거(GROUP BY, DISTINCT)

SELECT course_title, COUNT(*) AS 갯수 FROM orders o GROUP BY course_title

 

SELECT course_title  FROM orders o GROUP BY course_title

 

SELECT course_title  FROM orders o GROUP BY course_title

 

SELECT DISTINCT(course_title) FROM orders o

★ 정렬하기

SELECT * FROM payments p -- 1. 테이블에서 확인하기

 

SELECT * FROM payments p ORDER BY `date` ASC -- 2. date 기준으로 오름차순으로 정렬하기

 

SELECT * FROM payments p ORDER BY `date` DESC -- 3. date 기준으로 내림차순으로 정렬하기

 

SELECT * FROM ANIMAL_INS

 

SELECT ANIMAL_ID FROM ANIMAL_INS WHERE NAME is NOT NULL and NAME != '' ORDER BY ANIMAL_ID DESC