~고군분투 인생살이~

보호되어 있는 글입니다.

보호되어 있는 글입니다.

Table: Activity +---------------+---------+ | Column Name | Type | +---------------+---------+ | user_id | int | | session_id | int | | activity_date | date | | activity_type | enum | +---------------+---------+ There is no primary key for this table, it may have duplicate rows. The activity_type column is an ENUM of type ('open_session', 'end_session', 'scroll_down', 'send_message'). The table ..

보호되어 있는 글입니다.

Weather Observation Station 8 | HackerRank Query CITY names that start AND end with vowels. www.hackerrank.com 문제 조건 a,e,i,o,u로 시작하면서 끝나는 city 이름을 유니크하게 출력하시오. 문제 풀이 select distinct city from station where city regexp '^[a,e,i,o,u]' and city regexp '[a,e,i,o,u]$'

Weather Observation Station 7 | HackerRank Query the list of CITY names ending with vowels (a, e, i, o, u) from STATION. www.hackerrank.com 문제 조건 끝 글자가 a,e,i,o,u를 가지는 city 이름을 유니크하게 출력하시오 문제 풀이 # solution 1 select distinct city from station where city regexp '[a,e,i,o,u]$' # solution 2 select distinct city from station where city like '%a' or city like '%e' or city like '%i' or city like '%o' or..

Weather Observation Station 6 | HackerRank Query a list of CITY names beginning with vowels (a, e, i, o, u). www.hackerrank.com 문제 조건 a,e,i,o,u로 시작되는 city의 이름을 출력하시오 문제 풀이 # solution 1 select city from station where left(city,1) in ('a','e','i','o','u') # solution 2 select city from station where substr(city,1,1) in ('a','e','i','o','u')

Weather Observation Station 4 | HackerRank Find the number of duplicate CITY names in STATION. www.hackerrank.com 문제 조건 전체 city 수와 고유한 city 수의 차이를 구하시오 문제 풀이 SELECT (COUNT(CITY) - COUNT(DISTINCT CITY)) FROM STATION