Im between cherry

더보기 한 줄 요약 - INNER JOIN은 INNER JOIN할 원래 테이블에 찾는 테이블 값이 있으면, 찾는 테이블 값만 출력 - OUTER JOIN은 OUTER JOIN할 원래 테이블에 찾는 테이블 값이 있으면, 원래 테이블+찾는 테이블 값 출력 1. 정의 INNER JOIN - 서로 매칭되는 것만 엮어 조회한다. ​OUTER JOIN - 매칭 뿐만 아니라 매칭되지 않은 데이터도 함께 조회한다. OUTER JOIN에는 Left Outer Join, Right Outer Join, Full Outer Join이 있다. Left Join, Right Join은 미매칭 데이터도 조회할 테이블 방향이다. 따라서 Left Outer Join의 경우 왼쪽에 기입한 테이블이 매칭여부와 상관없이 모두 조회된다. ..

The Report Problem The Report | HackerRank Write a query to generate a report containing three columns: Name, Grade and Mark. www.hackerrank.com You are given two tables: Students and Grades. Students contains three columns ID, Name and Marks. 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 ..

Challenges Problem Challenges | HackerRank Print the total number of challenges created by hackers. www.hackerrank.com Julia asked her students to create some coding challenges. Write a query to print the hacker_id, name, and the total number of challenges created by each student. Sort your results by the total number of challenges in descending order. If more than one student created the same n..

Type of Triangle Problem Type of Triangle | HackerRank Query a triangle's type based on its side lengths. www.hackerrank.com 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 record in the table: Equilateral: It's a triangle with sides of equal length. Isosceles: It's a triangle with sides of equ..

Symmetric Pairs Problem Symmetric Pairs | HackerRank Write a query to output all symmetric pairs in ascending order by the value of X. www.hackerrank.com You are given a table, Functions, containing two columns: X and Y. Two pairs (X1, Y1) and (X2, Y2) are said to be symmetric pairs if X1 = Y2 and X2 = Y1. Write a query to output all such symmetric pairs in ascending order by the value of X. Lis..

Draw The Triangle 2 Problem Draw The Triangle 2 | HackerRank Draw the triangle pattern using asterisks. www.hackerrank.com P(R) represents a pattern drawn by Julia in R rows. The following pattern represents P(5): Write a query to print the pattern P(20). SET @num = 0; SELECT REPEAT('* ', @num := @num+1) FROM information_schema.tables LIMIT 20 SET @NUM:= 0; SELECT REPEAT('* ', @NUM := @NUM + 1) ..

Draw The Triangle 1 Problem Higher Than 75 Marks | HackerRank Query the names of students scoring higher than 75 Marks. Sort the output by the LAST three characters of each name. www.hackerrank.com P(R) represents a pattern drawn by Julia in R rows. The following pattern represents P(5): Write a query to print the pattern P(20). SET @number:= 21; SELECT REPEAT('* ', @number := @number -1) FROM i..

Average Population of Each Continent Problem Average Population of Each Continent | HackerRank Query the names of all continents and their respective city populations, rounded down to the nearest integer. www.hackerrank.com 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 t..