📌 SQL

-接続

cd /usr/local/mysql/bin
./mysql - uroot -p

-構造

-使用モード

mysql> create DATABASE opentutorials; #만들기  
mysql> SHOW DATABASES; #보여주기
mysql> USE opentutorials # 사용하기 

-テーブルの作成

CREATE TABLE topic(  
	id INT(11) NOT NULL AUTO_INCREMENT,		
    title VARCHAR(100) NOT NULL,  			
    description TEXT NULL,  
    created DATETIME NOT NULL,   
    author VARCHAR(30) NULL,  
    profile VARCHAR(100) NULL ,   
    PRIMARY KEY(id));

- CRUD

- create (insert)

USE 사용할데이베이스
INSERT INTO topic (title,description,created,author,profile) VALUES('mysql','my sql is...',NOW(),'egoing','developer');

SELECT * FROM topic;  #확인

- select(read)

SELECT id,title,created, author FROM topic WHERE author="egoing";
SELECT id,title,created, author FROM topic WHERE author="egoing" ORDER BY id DESC;

- update

UPDATE topic SET description='ORACLE IS,,,,,,', title = "ORACLE" WHERE id=2; #id 값이 2인 행에 대해서

- delete

DELETE FROM topic WHERE ID = 5; 

- Join

SELECT * FROM topic LEFT JOIN author ON topic.author_id = author.id; #전체 

SELECT topic.id,title,description,created,name,profile FROM topic LEFT JOIN author ON topic.author_id = author.id;
# 전체에서 몇개 빼고 join

SELECT topic.id as topic_id,title,description,created,name,profile FROM topic LEFT JOIN author ON topic.author_id = author.id;
#첫번째 칼럼이 topic_id로 바뀜