SQL
1.SQL 중급 - Group By & Having
COUNT AVG 종합 사용 Group By + Order By 
We define an employee's total earnings to be their monthly worked, and the maximum total earnings to be the maximum total earnings for any employee i
3.SQL ) Case-When-End
https://extbrain.tistory.com/46
4.184. Department Highest Salary_서브쿼리
https://leetcode.com/problems/department-highest-salary/
5.Challenges
https://www.hackerrank.com/challenges/challenges/problem?isFullScreen=true
6.Top Earners
https://www.hackerrank.com/challenges/earnings-of-employees/problem?h_r=internal-search
7.SQL 중급 ) UNION, UNION ALL
: 데이터를 위아래로 연결 두 개 테이블의 컬럼 수, 컬럼 데이터 형식이 모두 일치해야한다.UNION 연산은 두 개의 테이블을 하나로 합치면서 중복된 데이터를 제거한다.UNION은 정렬을 발생시킨다.Two pairs (X1, Y1) and (X2, Y2) are sai
8.SQL 중급 ) CASE를 활용한 테이블 피봇
백문이불여일타CASE를 활용한 테이블 피봇https://www.w3schools.com/sql/trysql.asp?filename=trysql_select_all
9.SQL 중급 ) 해커랭크_Type of Triangle
Write a query identifying the type of each record in the TRIANGLES table using its three side lengths. Output one of the following statements for each
10.180. Consecutive Numbers_조인,윈도우함수
https://leetcode.com/problems/consecutive-numbers/
11.The Report_조인
https://www.hackerrank.com/challenges/the-report/problem?h_r=internal-search
12.SQL) 윈도우 함수 뿌시기
13.184. Department Highest Salary_윈도우함수(MAX)
https://leetcode.com/problems/department-highest-salary/
14.SQL 중급 ) JOIN
문제:Given the CITY and COUNTRY tables, query the names of all cities where the CONTINENT is 'Africa'.Note: CITY.CountryCode and COUNTRY.Code are matchi
15.185. Department Top Three Salaries_윈도우함수(DENSE_RANK())
https://leetcode.com/problems/department-top-three-salaries/
16.184. Department Highest Salary_윈도우함수(RANK())
https://leetcode.com/problems/department-highest-salary/description/
17.[백문이불여일타:고급] 정규표현식 응용
https://www.hackerrank.com/challenges/weather-observation-station-6/problem?isFullScreen=true
18.사용자 정의 함수 (User-Defined Function)
with 데이터리안:데이터분석 고급
19.❌ 177. Nth Highest Salary (Case,If, Limit,Offset)
Case,If, Limit,Offset 를 활용해서 3가지 방법으로 풀기
20.[MySQL]CASE vs IF Statement vs IF function
CASE vs IF Statement vs IF function 비교