~고군분투 인생살이~

Weather Observation Station 18 | HackerRank Query the Manhattan Distance between two points, round or truncate to 4 decimal digits. www.hackerrank.com 문제 조건 Consider P1(a,b) and P2(c,d) to be two points on a 2D plane. happens to equal the minimum value in Northern Latitude (LAT_N in STATION). happens to equal the minimum value in Western Longitude (LONG_W in STATION). happens to equal the maximu..

Japanese Cities' Names | HackerRank In this challenge, you will query a list of all the Japanese cities' names. www.hackerrank.com 문제 조건 Query the names of all the Japanese cities in the CITY table. The COUNTRYCODE for Japan is JPN. 문제 풀이 select name from city where countrycode = 'JPN'

1. 문제 설명 Query the list of CITY names from STATION that do not end with vowels. Your result cannot contain duplicates. Input Format The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 2. 문제 풀이 3. 결과 SELECT DISTINCT CITY FROM STATION WHERE CITY REGEXP '[^AEIOU]$.*'

1. 문제 설명 Query the list of CITY names from STATION that do not start with vowels. Your result cannot contain duplicates. Input Format The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 2. 문제 풀이 3. 결과 SELECT DISTINCT CITY FROM STATION WHERE CITY REGEXP '^[^AEIOU].*'

1. 문제 설명 Query the list of CITY names from STATION which have vowels (i.e., a, e, i, o, and u) as both their first and last characters. Your result cannot contain duplicates. Input Format The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 2. 문제 풀이 3. 결과 SELECT DISTINCT CITY FROM STATION WHERE CITY REGEXP('^[AEIOU]') AND CITY REGEX..

1. 문제 설명 Query the list of CITY names ending with vowels (a, e, i, o, u) from STATION. Your result cannot contain duplicates. Input Format The STATION table is described as follows: where LAT_N is the northern latitude and LONG_W is the western longitude. 2. 문제 풀이 3. 결과 SELECT DISTINCT city FROM STSATION WHERE city REGEXO '[AEIOUaeiou]$.*'

요약 : 해당 튜토리얼에서는 MySQL DELETE JOIN문을 이용하여 여러 테이블에서 데이터를 삭제하는 방법을 보여줍니다. 이전 튜토리얼에서 배운 내용 : 여러 테이블에 대한 단일 DELETE문 자식 테이블(child table)에 foreign key에 대한 ON DELETE CASCADE 참조 작업이 있는 여러 관련 테이블에 대한 단일 DELETE문 이번 튜토리얼에서는 DELETE문과 함께 INNER JOIN 또는 LEFT JOIN 절을 사용하여 여러 테이블에서 데이터를 삭제(제거)하는 보다 유연한 방법을 소개합니다. MySQL DELETE JOIN with INNER JOIN MySQL은 DELETE 문에서 INNER JOIN절을 사용하여 테이블에서 행을 삭제하고 다른 테이블에서 일치하는 행 도..

1. 문제 설명 Table: Person +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | email | varchar | +-------------+---------+ id is the primary key column for this table. Each row of this table contains an email. The emails will not contain uppercase letters. Write an SQL query to delete all the duplicate emails, keeping only one unique email with the smallest id. ..