Day1

https://school.programmers.co.kr/learn/courses/30/lessons/59407

SELECT ANIMAL_ID FROM ANIMAL_INS WHERE NAME IS NOT NULL;

https://school.programmers.co.kr/learn/courses/30/lessons/59035

SELECT NAME, DATETIME FROM ANIMAL_INS ORDER BY ANIMAL_ID DESC;

https://school.programmers.co.kr/learn/courses/30/lessons/59408

SELECT SUM(CNT) AS CNT FROM ( SELECT COUNT(DISTINCT(NAME)) AS CNT FROM ANIMAL_INS WHERE NAME IS NOT NULL ) A;

SELECT SUM(NAME) COUNT FROM ( SELECT COUNT(DISTINCT(NAME)) AS NAME FROM ANIMAL_INS WHERE NAME IS NOT NULL GROUP BY NAME ) A GROUP BY NAME;