오늘도 배운다

문제 Julia just finished conducting a coding contest, and she needs your help assembling the leaderboard! Write a query to print the respective hacker_id and name of hackers who achieved full scores for more than one challenge. Order your output in descending order by the total number of challenges in which the hacker earned a full score. If more than one hacker received full scores in same number..

문제 Amber's conglomerate corporation just acquired some new companies. Each of the companies follows this hierarchy (See Fig1): Given the table schemas below, write a query to print the company_code, founder name, total number of lead managers, total number of senior managers, total number of managers, and total number of employees. Order your output by ascending company_code. Note: The tables ma..

문제 You are given two tables: Students and Grades. Students contains three columns ID, Name and Marks. Grades contains the following data: Grades contains the following data: Ketty gives Eve a task to generate a report containing three columns: Name, Grade and Mark. Ketty doesn't want the NAMES of those students who received a grade lower than 8. The report must be in descending order by grade --..

문제 Given the CITY and COUNTRY tables, query the names of all the continents (COUNTRY.Continent) and their respective average city populations (CITY.Population) rounded down to the nearest integer. Note: CITY.CountryCode and COUNTRY.Code are matching key columns. 제출답안(MySQL) SELECT continent, FLOOR(AVG(ct.population)) FROM city as ct JOIN country ctr ON ct.countrycode = ctr.code GROUP BY continen..

문제 A median is defined as a number separating the higher half of a data set from the lower half. Query the median of the Northern Latitudes (LAT_N) from STATION and round your answer to 4 decimal places. 제출답안(MySQL) SELECT ROUND(lat_n, 4) FROM (SELECT lat_n, PERCENT_RANK() OVER (ORDER BY lat_n) AS pct FROM station) tb_pct WHERE pct = 0.5 풀이(MySQL) 더보기 오라클과 달리 MySQL은 MEDIAN 함수를 지원하지 않음 >> 따라서 직접 ..

문제 Consider P1(a,c) and P2(b,d) to be two points on a 2D plane where (a,b) are the respective minimum and maximum values of Northern Latitude (LAT_N) and (c,d) are the respective minimum and maximum values of Western Longitude (LONG_W) in STATION. Query the Euclidean Distance between points and and format your answer to display decimal digits. 제출답안(MySQL) -- Euclidean Distance between (a, c) and..

문제 Consider P1(a,b) and P2(c, d) to be two points on a 2D plane. 'a' happens to equal the minimum value in Northern Latitude (LAT_N in STATION). 'b' happens to equal the minimum value in Western Longitude (LONG_W in STATION). 'c' happens to equal the maximum value in Northern Latitude (LAT_N in STATION). 'd' happens to equal the maximum value in Western Longitude (LONG_W in STATION). Query the M..

문제 Query the Western Longitude (LONG_W)where the smallest Northern Latitude (LAT_N) in STATION is greater han 38.7780. Round your answer to 4 decimal places. 제출답안(MySQL) SELECT ROUND(long_w, 4) FROM station WHERE lat_n = (SELECT MIN(lat_n) FROM station WHERE lat_n > 38.7780 ) 문제 바로가기(MySQL)