[Programmers] SQL 공부(2)

Problem URL : 역순 정렬하기

SELECT NAME, DATETIME FROM ANIMAL_INS ORDER BY ANIMAL_ID DESC

Problem URL : 최솟값 구하기

SELECT MIN(DATETIME) FROM ANIMAL_INS

Problem URL : 동명 동물 수 찾기

SELECT NAME, COUNT(NAME) "COUNT"
FROM ANIMAL_INS 
GROUP BY NAME 
HAVING COUNT(NAME) >= 2 
ORDER BY NAME

Problem URL : 이름이 있는 동물의 아이디

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

Problem URL : 있었는데요 없었습니다

SELECT A.ANIMAL_ID, A.NAME 
FROM ANIMAL_INS A 
LEFT JOIN ANIMAL_OUTS B 
ON A.ANIMAL_ID = B.ANIMAL_ID 
WHERE A.DATETIME > B.DATETIME
ORDER BY A.DATETIME

Problem URL : 이름에 el이 들어가는 동물 찾기

SELECT ANIMAL_ID, NAME
FROM ANIMAL_INS
WHERE NAME LIKE '%EL%' AND ANIMAL_TYPE = 'Dog'
ORDER BY NAME