오우진

테이블 생성 코드 Create table If Not Exists Users (user_id int, user_name varchar(20)) Create table If Not Exists Register (contest_id int, user_id int) Truncate table Users insert into Users (user_id, user_name) values ('6', 'Alice') insert into Users (user_id, user_name) values ('2', 'Bob') insert into Users (user_id, user_name) values ('7', 'Alex') Truncate table Register insert into Register (conte..

테이블 생성코드 Create table If Not Exists Users (user_id int, name varchar(40)) Truncate table Users insert into Users (user_id, name) values ('1', 'aLice') insert into Users (user_id, name) values ('2', 'bOB') 문제 풀이코드 SELECT user_id, concat(upper(left(name,1)), lower(substring(name,2))) AS name FROM Users ORDER BY user_id; 해설 첫글자는 개문자, 나머지는 소문자로 출력해야 하므로 name의 첫글자를 대문자로 만든것과 name의 2번째부터 나머지를 소문자로 만든것..

테이블 생성 코드 Create table If Not Exists Project (project_id int, employee_id int) Create table If Not Exists Employee (employee_id int, name varchar(10), experience_years int) Truncate table Project insert into Project (project_id, employee_id) values ('1', '1') insert into Project (project_id, employee_id) values ('1', '2') insert into Project (project_id, employee_id) values ('1', '3') insert int..

테이블 생성코드 Create table If Not Exists Triangle (x int, y int, z int) Truncate table Triangle insert into Triangle (x, y, z) values ('13', '15', '30') insert into Triangle (x, y, z) values ('10', '20', '15') 문제 gorufzhem SELECT x,y,z, CASE WHEN x+y>z AND y+z>x AND x+z>y THEN 'Yes' ELSE 'No' END AS triangle FROM Triangle 풀이 SELECT 절에서 CASE WHEN THEN 구문을 사용한다. 그리거 END AS 로 triangle로 지정한다.

테이블 생성코드 Create table If Not Exists Sales (sale_id int, product_id int, year int, quantity int, price int) Create table If Not Exists Product (product_id int, product_name varchar(10)) Truncate table Sales insert into Sales (sale_id, product_id, year, quantity, price) values ('1', '100', '2008', '10', '5000') insert into Sales (sale_id, product_id, year, quantity, price) values ('2', '100', '200..

테이블 생성 코드 Create table If Not Exists Views (article_id int, author_id int, viewer_id int, view_date date) Truncate table Views insert into Views (article_id, author_id, viewer_id, view_date) values ('1', '3', '5', '2019-08-01') insert into Views (article_id, author_id, viewer_id, view_date) values ('1', '3', '6', '2019-08-02') insert into Views (article_id, author_id, viewer_id, view_date) value..

EVEN NUMBER : 짝수 ODD NUMBER : 홀수 테이블 생성코드 Create table If Not Exists cinema (id int, movie varchar(255), description varchar(255), rating float(2, 1)) Truncate table cinema insert into cinema (id, movie, description, rating) values ('1', 'War', 'great 3D', '8.9') insert into cinema (id, movie, description, rating) values ('2', 'Science', 'fiction', '8.5') insert into cinema (id, movie, descripti..

테이블 생성 코드 Create table If Not Exists Person (personId int, firstName varchar(255), lastName varchar(255)) Create table If Not Exists Address (addressId int, personId int, city varchar(255), state varchar(255)) Truncate table Person insert into Person (personId, lastName, firstName) values ('1', 'Wang', 'Allen') insert into Person (personId, lastName, firstName) values ('2', 'Alice', 'Bob') Trunc..

테이블 생성코드 Create table If Not Exists World (name varchar(255), continent varchar(255), area int, population int, gdp bigint) Truncate table World insert into World (name, continent, area, population, gdp) values ('Afghanistan', 'Asia', '652230', '25500100', '20343000000') insert into World (name, continent, area, population, gdp) values ('Albania', 'Europe', '28748', '2831741', '12960000000') ins..

테이블 생성하기 Create table If Not Exists Person (id int, email varchar(255)) Truncate table Person insert into Person (id, email) values ('1', 'a@b.com') insert into Person (id, email) values ('2', 'c@d.com') insert into Person (id, email) values ('3', 'a@b.com') 문제 결과코드 # Write your MySQL query statement below SELECT email AS Email FROM Person GROUP BY Email HAVING COUNT(Email)>=2; 해설 GROUP BY로 emai..