SQL 연습 DDL, DML

DDL (Data Definition Language), 

CREATE TABLE
 creates a new table.

ALTER TABLE
 changes an existing table.

 

DML (Data Manipulation Language)

INSERT INTO
 adds a new row to a table.
SELECT
 queries data from a table.
UPDATE
 edits a row in a table.
DELETE FROM
 deletes rows from a table.

 

기본적인 SQL 구문들을 아래와 같이 사용하여 보았다.

  CREATE TABLE friends (
    id INTEGER,
    name TEXT,
    birthday DATE
  );
  INSERT INTO friends 
  VALUES (1,'Ororo Munroe', '1940-05-30');
  INSERT INTO friends 
  VALUES (2,'Hyunwoo Lee', '1993-05-30');
  INSERT INTO friends 
  VALUES (3,'Dokyu Ha', '1993-05-30');

  UPDATE friends
  SET name = 'Storm'
  WHERE name = 'Ororo Munroe';

  ALTER TABLE friends
  ADD email TEXT;

  UPDATE friends
  SET email = 'storm@codecademy.com'
  WHERE id = 1;
  UPDATE friends
  SET email = 'hyunwooLee@codecademy.com'
  WHERE id = 2;
  UPDATE friends
  SET email = 'dokyeHa@codecademy.com'
  WHERE id = 3;

  DELETE FROM friends
  WHERE id = 1;
  
  SELECT * FROM friends;