목록전체 글 (174)

조컴퓨터

hackerrank Draw The Triangle 2

1) SET 1-1) SET @row := 0; 2) * 반복 2-1) REPEAT( "* ", @row := @row + 1 ) 3) INFORMATION_SCHEMA.tables 3-1) SET @row :=0; SELECT REPEAT("* ", @row := @row + 1 ) FROM INFORMATION_SCHEMA.tables 4) where절 4-1) SET @row := 0; SELECT REPEAT("* ", @row := @row + 1 ) FROM INFORMATION_SCHEMA.tables WHERE @row < 20; 4-1) 결과 이하 20줄까지 출력된다. SUCCESS!!
HackerRank/SQL 2021. 2. 18. 23:55
hackerrank Weather Observation Station 6

1) 정규표현식 1-1) SELECT city FROM STATION WHERE city REGEXP '^[aeiou]'; 1-1) 결과 mysql 정규표현식 regexp 1) 문자열에 '한글'이 표함된 경우 1-1) SELECT * FROM 테이블명 WHERE name REGEXP '[가-힣]'; 2) 문자열의 시작이 '한글'인 경우 2-1) SELECT * FROM 테이블명 WHERE name REGEXP '^[가-힣]'; 3) 문자열의 끝이 '한글'인 경우 3-1) SELECT * FROM 테이블명 WHERE name REGEXP '[가-힣]$'; 4) 모든 문자열이 '한글'인 경우 4-1) SELECT * FROM 테이블명 WHERE name REGEXP '^[가-힣]+$'; 5) 문자열에 '영어..
HackerRank/SQL 2021. 1. 31. 00:34
hackerrank Weather Observation Station 5

1) 짧은 도시명 1-1) SELECT city, LENGTH(city) FROM STATION ORDER BY LENGTH(city), city; 1-1) 결과 1-2) SELECT * FROM ( SELECT city, LENGTH(city) FROM STATION ORDER BY LENGTH(city), city ) WHERE rownum = 1; 1-2) 결과 2) 가장 긴 도시명 2-1) SELECT city, LENGTH(city) FROM STATION ORDER BY LENGTH(city) DESC, city DESC; 2-1) 결과 2-2) SELECT * FROM ( SELECT city, LENGTH(city) FROM STATION ORDER BY LENGTH(city) DESC, ..
HackerRank/SQL 2021. 1. 31. 00:05
hackerrank Weather Observation Station 3

1) MOD(id, 2) = 0 1-1) SELECT city FROM STATION WHERE MOD(id, 2) = 0; 1-1) 결과 2) 중복 체크 2-1) SELECT city FROM STATION WHERE MOD(id, 2) = 0 GROUP BY city; 2-1) 결과 SUCCESS!!
HackerRank/SQL 2021. 1. 30. 23:38
전자정부표준프레임워크(20년 6차) 수료증

표준프레임워크 온라인 교육(20년 6차) 수료증 좋은 이수 과정이었다.
카테고리 없음 2021. 1. 23. 19:07
hackerrank Symmetric Pairs

1) X = Y 1-1) SELECT X, Y FROM Functions WHERE X = Y GROUP BY X, Y 1-1) 결과 1-2) COUNT(*) SELECT X, Y, COUNT(*) FROM Functions WHERE X = Y GROUP BY X, Y HAVING COUNT(*) = 2 1-2) 결과 2) X1 = Y1 AND X2 = Y2 2-1) SELECT f1.X, f1.Y FROM Functions f1, Functions f2 WHERE f1.X = f2.Y AND f2.X = f1.Y AND f1.X < f1.Y -- f1.X f1.Y / 단, 이 경우에는 중첩되므로 f1.X < f1.Y 인 한 가지 경우만 사용 2-1) 결과 3) UNION 3-1) SELECT X, Y..
HackerRank/SQL 2021. 1. 18. 21:02
leetcode 197. Rising Temperature

1) SELF JOIN 1-1) SELECT * FROM Weather w1, Weather w2 WHERE DATE_ADD(w1.recordDate, INTERVAL 1 DAY) = w2.recordDate AND w1.Temperature < w2.Temperature 1-1) 결과 {"headers": ["Id", "RecordDate", "Temperature", "Id", "RecordDate", "Temperature"], "values": [[1, "2015-01-01", 10, 2, "2015-01-02", 25], [3, "2015-01-03", 20, 4, "2015-01-04", 30]]} 2) w2.Id 2-1) SELECT w2.Id AS Id FROM Weather w1, Wea..
LeetCode/SQL 2021. 1. 18. 20:02
leetcode 181. Employees Earning More Than Their Managers

1) SELF JOIN 1-1) SELECT * FROM Employee e1, Employee e2 WHERE e1.Id = e2.ManagerId 1-1) 결과 {"headers": ["Id", "Name", "Salary", "ManagerId", "Id", "Name", "Salary", "ManagerId"], "values": [[3, "Sam", 60000, null, 1, "Joe", 70000, 3], [4, "Max", 90000, null, 2, "Henry", 80000, 4]]} 2) e1.Salary(매니저 급여) < e2.Salary(직원 급여) SELECT * FROM Employee e1, Employee e2 WHERE e1.Id = e2.ManagerId AND e1.S..
LeetCode/SQL 2021. 1. 18. 18:25
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