[비트연산자] 조건에 맞는 개발자 찾기

https://school.programmers.co.kr/learn/courses/30/lessons/276034

프로그래머스

조인이용

DISTINCT를 붙여야 한다. 왜냐하면 Python과 C# 둘다 가지고 있는 경우가 있을 수 있다.

SELECT DISTINCT ID, EMAIL, FIRST_NAME, LAST_NAME
FROM DEVELOPERS AS A
LEFT JOIN SKILLCODES AS B ON B.CODE & A.SKILL_CODE = B.CODE
WHERE B.NAME = "C#" OR B.NAME ="Python"
ORDER BY ID ASC;

 

서브쿼리이용

SELECT ID, EMAIL, FIRST_NAME, LAST_NAME
FROM DEVELOPERS 
WHERE DEVELOPERS.SKILL_CODE & (SELECT CODE FROM SKILLCODES WHERE NAME="C#") 
OR DEVELOPERS.SKILL_CODE & (SELECT CODE FROM SKILLCODES WHERE NAME="Python")
ORDER BY ID ASC;

SELECT ID, EMAIL, FIRST_NAME, LAST_NAME
FROM DEVELOPERS 
WHERE DEVELOPERS.SKILL_CODE & (SELECT CODE FROM SKILLCODES WHERE NAME="C#") = (SELECT CODE FROM SKILLCODES WHERE NAME="C#")
OR DEVELOPERS.SKILL_CODE & (SELECT CODE FROM SKILLCODES WHERE NAME="Python") =  (SELECT CODE FROM SKILLCODES WHERE NAME="Python")
ORDER BY ID ASC;