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데이터 분석/코딩

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JOIN과 BETWEEN 활용, ORDER BY절의 조건문 취준 스터디 JOIN과 BETWEEN 활용, ORDER BY절의 조건문 https://www.hackerrank.com/challenges/the-report/problem?isFullScreen=true The Report | HackerRank Write a query to generate a report containing three columns: Name, Grade and Mark. www.hackerrank.com 내가 쓴 답 with temp as ( select name, marks, case when marks=90 then 10 when marks between 10 and 89 then substr(marks, 1, 1)+1 end as grade from students ) sel.. 공감수 0 댓글수 0 2024. 4. 15.
조건문 및 SUBSTR로 문제 쉽게 풀기 SQL 취업 스터디 모임 https://www.hackerrank.com/challenges/the-pads/problem?isFullScreen=true The PADS | HackerRank Query the name and abbreviated occupation for each person in OCCUPATIONS. www.hackerrank.com select concat(name, case when occupation = "actor" then '(A)' when occupation = 'doctor' then '(D)' when occupation = 'professor' then '(P)' when occupation = 'singer' then '(S)' end 1) d from occ.. 공감수 0 댓글수 0 2024. 4. 3.
TRUNCATE, CROSS JOIN 및 LEFT JOIN 코드카타 문제 158 Weather Observation Station 13 TRUNCATE 함수 Weather Observation Station 13 | HackerRank Query the sum of Northern Latitudes having values greater than 38.7880 and less than 137.2345, truncated to 4 decimal places. www.hackerrank.com select truncate(sum(lat_n), 4) from station where lat_n > 38.7880 and lat_n < 137.2345 round함수와 비슷하지만, 반올림이 아니라 내림하는 함수. 어렵진 않지만 처음 써본 함수라 기록. 사실 문제에 trun.. 공감수 0 댓글수 0 2024. 3. 15.
REGEXP [문제 156. The Blunder] 문자열 교체 - regexp_replace select round(avg(salary), 0) - round(avg(regexp_replace(salary, 0, '')), 0) from employees 공감수 0 댓글수 0 2024. 2. 27.
서울시 (청년) 인구 데이터 가공 - 서브쿼리, JOIN, 숫자인식 프로젝트 *원데이터(출처 : 서울시 열린데이터 광장) select t.지역, t.전체 as 전체인구, f.전체 as 여성인구, m.전체 as 남성인구, round(f.전체/m.전체, 4) as 전체여남성비, round(f.전체/t.전체*100, 2) as 전체인구중여성비중, t.청년인구 as 전체청년인구, round(t.청년인구/t.전체*100, 2) as 청년인구비중, f.청년인구 as 여성청년인구, m.청년인구 as 남성청년인구, round(f.청년인구/m.청년인구, 4) as 청년여남성비, round(f.청년인구/t.청년인구*100, 2) as 청년중여성비중, round(f.청년인구/t.전체*100, 2) as 전체인구중청년여성비중 from (select 지역, 전체, 청년인구 from totalp.. 공감수 0 댓글수 0 2024. 2. 8.
SQL - 정규표현식 카타 문제 모음 SQL 카타 select distinct city from station where city regexp '^[aeiou].*[aeiou]$' select distinct city from station where city not regexp '^[aeiou]' select distinct city from station where city not regexp '[aeiou]$' 정답 select distinct city from station where city not regexp '^[aeiou]' and city not regexp '[aeiou]$' *주의 select distinct city from station where city not regexp '^[aeiou].*[aeiou]$' 오답.. 공감수 0 댓글수 0 2024. 2. 2.
UNION, 정규표현식 카타 (SELECT city, length(city) FROM STATION ORDER BY length(CITY) ASC,CITY ASC limit 1) union (select city, length(city) from station order by length(city) desc, city asc limit 1) 잠시 헷갈렸던 문제라 기록 select city from station where city regexp '^[aeiou]' 어제 새로 공부했던 정규표현식을 바로 써먹었던 문제라 복습 차원에서 기록. 공감수 0 댓글수 0 2024. 2. 1.
정규 표현식 SQL 카타 문제126 Find Users With Valid E-Mails : 정규식 LeetCode - The World's Leading Online Programming Learning Platform Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com select * from users where mail regexp '^[a-zA-Z][a-zA-Z0-9_.-]*@leetcode[.]com$' 정답 해설 ^[a-zA-Z] : 맨 앞글자가 소문자 혹은 대문자 알파벳으로 이뤄져.. 공감수 0 댓글수 0 2024. 1. 31.
INTERSECT, GROUP_CONCAT, 집계함수 SQL 카타 문제 118. 585. investment in 2016 : where 활용, intersect, 집계함수 문법 LeetCode - The World's Leading Online Programming Learning Platform Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com 작성한 정답 select round(sum(tiv_2016) over (), 2) as tiv_2016 from insurance where tiv_2015 in (select tiv_20.. 공감수 0 댓글수 0 2024. 1. 30.
윈도우 함수-집계 행 지정 카타 문제 116. 1321. Restaurant Growth : 윈도우 함수-집계 행 지정, limit 활용(offsetX) LeetCode - The World's Leading Online Programming Learning Platform Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com with cte as (select visited_on, sum(amount) as amount from customer group by visited_on) select visited_.. 공감수 0 댓글수 0 2024. 1. 29.
Exchange Seats if(ifnull) 및 case when 조건문 동시 활용, union all 카타 문제 114. 626. Exchange Seats if(ifnull), case when 조건문 활용 LeetCode - The World's Leading Online Programming Learning Platform Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com Write a solution to swap the seat id of every two consecutive students. If the number of students is odd, the id of.. 공감수 0 댓글수 0 2024. 1. 26.
1. WHERE, UNION, DISTINCT, 2. WITH, 윈도우함수 카타 문제 110. 1164. Product Price at a Given Date : where, union, distint 활용 LeetCode - The World's Leading Online Programming Learning Platform Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com Write a solution to find the prices of all products on 2019-08-16. Assume the price of all products b.. 공감수 0 댓글수 0 2024. 1. 25.
SQL 1/24 - where, union, lead/lag SQL 코드카타 문제 107. 1789. Primary Department for Each Employee : where, union 활용 LeetCode - The World's Leading Online Programming Learning Platform Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com Employees can belong to multiple departments. When the employee joins other departments, they nee.. 공감수 0 댓글수 0 2024. 1. 24.
1/21 - WHERE IN, HAVING 활용 SQL 카타 문제 104. 619. Biggest Single Number LeetCode - The World's Leading Online Programming Learning Platform Level up your coding skills and quickly land a job. This is the best place to expand your knowledge and get prepared for your next interview. leetcode.com 오답 select max(num) from mynumbers group by num having count(*) = 1 싱글인 숫자 다 나와뻘임. 아침이라 잠이 제대로 덜 깬듯ㅋㅋ 정답 select max(num) as num from m.. 공감수 0 댓글수 0 2024. 1. 23.

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