[데이터분석 부트캠프] SQL 코드카타 #1

1. 이름이 있는 동물의 아이디 (https://school.programmers.co.kr/learn/courses/30/lessons/59407)

SELECT ANIMAL_ID
FROM ANIMAL_INS
WHERE NAME IS NOT NULL
ORDER BY ANIMAL_ID

 

2. 역순 정렬하기 (https://school.programmers.co.kr/learn/courses/30/lessons/59035)

SELECT NAME, DATETIME
FROM ANIMAL_INS
ORDER BY ANIMAL_ID DESC

 

3. 중복 제거하기 (https://school.programmers.co.kr/learn/courses/30/lessons/59408)

SELECT COUNT(DISTINCT NAME) AS count 
FROM ANIMAL_INS
WHERE NAME IS NOT NULL

 

4. 동물의 아이디와 이름 (https://school.programmers.co.kr/learn/courses/30/lessons/59403)

SELECT ANIMAL_ID, NAME
FROM ANIMAL_INS
ORDER BY ANIMAL_ID

 

5. 동물 수 구하기 (https://school.programmers.co.kr/learn/courses/30/lessons/59406)

SELECT COUNT(ANIMAL_ID) AS count
FROM ANIMAL_INS

 

NULL: 값이 없는 것
DISTINCT: 고유의 값
ORDER BY: 정렬
AS Alias: 별명