Database

Show

SHOW DATABASES;

Create

CREATE DATABASE IF NOT EXISTS <database>;

Drop

DROP DATABASE IF EXISTS <database>;

Use

USE <database>;

Table

Create

CREATE <OR REPLACE TABLE | TABLE IF NOT EXISTS> <table>
(   <column> <type> AUTO_INCREMENT,
    <column> <type> NOT NULL,
    <column> <type> PRIMARY KEY,
    <column> <type> UNIQUE,
    <column> <type> CHECK (<condition>),
    <column> <type> DEFAULT <value>,
    PRiMARY KEY(<column>),
    FOREIGN KEY(<column>)
        REFERENCES <table>(<column>)
        ON UPDATE <way>
        ON DELETE <way>
);

CREATE <OR REPLACE TABLE | TABLE IF NOT EXISTS> <table>
    <select statement>;                                 -- select 문을 이용한 table 만들기

Option	Explanation	Way
AUTO_INCREMENT	1부터 자동으로 숫자가 지정, 지정한 열이 PRIMARY KEY나 UNIQUE여야 함
NOT NULL	NULL이 입력될 수 없음
UNIQUE	같은 값이 올 수 없음
PRIMARY KEY	NOT NULL + UNIQUE
FOREIGN KEY	다른 테이블의 열과 연결, 지정한 열이 PRIMARY KEY나 UNIQUE여야 함
	CASCADE	함께 작동
	SET NULL	NULL로 설정
	RESTRICT	error 발생

Alter

ALTER TABLE <table> ADD COLUMN <column> <type> <option>;             -- add column

ALTER TABLE <table> ADD COLUMN <column> <type> <option> <column>;    -- add column behind

ALTER TABLE <table> MODIFY COLUMN <column> <type> <option>;          -- modify column

ALTER TABLE <table> CHANGE COLUMN <column> <column> <type> <option>; -- change column name

ALTER TABLE table_name DROP COLUMN <column>;                         -- drop column

ALTER TABLE <table> RENAME <table>;                                  -- change table name

ALTER TABLE <table>
    ADD CONSTRAINT PRIMARY KEY(<column>);                            -- primary key 지정

ALTER TABLE <table>
    ADD CONSTRAINT FOREIGN KEY(<column>)
        REFERENCES <table> (<column>)
        ON UPDATE <way>
        ON DELETE <way>;                                             -- foreign key 지정

ALTER TABLE <table>
    ADD CONSTRAINT UNIQUE(<column>);                                 -- unique 지정

ALTER TABLE <table> DROP  PRIMARY KEY;                               -- primary key 삭제

ALTER TABLE <table> DROP  FOREIGN KEY;                               -- foreign key 삭제

ALTER TABLE <table> DROP  UNIQUE;                                    -- unique 삭제

Drop

DROP TABLE IF EXISTS <table>;

View

Create

CREATE <OR REPLACE VIEW | VIEW IF NOT EXISTS> <view> AS
    <select statement>
    <WITH CHECK OPTION>;

Alter

ALTER VIEW <view> AS
    <select statement>
    <WITH CHECK OPTION>;

Drop

DROP VIEW IF EXISTS <view>;

Data

Insert

INSERT INTO <table | view> (<column>, <column>, ...)
    VALUES (<value>, <value>, ...), (<value>, <value>, ...), ...; -- insert values

INSERT INTO <table | view> (<column>, <column>, ...)
    <select statement>;                                           -- insert table

Update

UPDATE <table | view>
    SET <column> = <value>, <column> = <value>, ...
    WHERE <condition>;

Delete

DELETE FROM <table | view>
    WHERE <condition>;                                            -- delete data

TRUNCATE TABLE <table | view>;                                    -- delete all

Show

DESC <table | view>;                                              -- 정보를 보여줌

SHOW CREATE <TABLE | VIEW> <table | view>;                        -- 소스코드를 보여줌

CHECK TABLE <table | view>;                                       -- 상태를 확인

Select

SELECT <column> <name>, <column> <name>, ...
    FROM <table>
    WHERE <condition>
    GROUP BY <column>
    HAVING <condition>
    ORDER BY <column> <ASC | DESC>, <column2> <ASC | DESC> ...
    LIMIT <offset> <number>;

Join

Inner Join/Self Join

SELECT <table>.<column> <name>, <table>.<column> <name>, ...
    FROM <table> <name>
        INNER JOIN  <table> <name>
        ON <table>.<column> = <table>.<column>;              -- inner join / self join

Left Outer Join

SELECT <table>.<column> <name>, <table>.<column> <name>, ...
    FROM <table> <name>
        LEFT OUTER JOIN  <table> <name>
        ON <table>.<column> = <table>.<column>;              -- left outer join

Right Outer Join

SELECT <table>.<column> <name>, <table>.<column> <name>, ...
    FROM <table> <name>
        RIGHT OUTER JOIN  <table> <name>
        ON <table>.<column> = <table>.<column>;              -- right outer join

Full Outer Join

SELECT <table>.<column> <name>, <table>.<column> <name>, ...
    FROM <table> <name>
        LEFT OUTER JOIN  <table> <name>
        ON <table>.<column> = <table>.<column>
UNION
SELECT <table>.<column> <name>, <table>.<column> <name>, ...
    FROM <table> <name>
        RIGHT OUTER JOIN  <table> <name>
        ON <table>.<column> = <table>.<column>;              -- full outer join

Cross Join

SELECT <table>.<column> <name>, <table>.<column> <name>, ...
    FROM <table> <name>
        CROSS JOIN JOIN  <table> <name>                      -- cross join

Procedure

Create

DELIMITER $$
CREATE PROCEDURE <procedure>(IN <variable> <type>, OUT <variable> <type>)
BEGIN
    <statement>;
END $$
DELIMITER ;

Call

CALL <procedure>(<value>, @<variable>);

Drop

DROP PROCEDURE IF EXISTS <procedure>;

Function

Create

DELIMITER $$
CREATE Function <function>(<variable> <type>) RETURNS <type>
BEGIN
    <statement>;
    RETURN <value>;
END $$
DELIMITER ;

Call

SELECT <function>(<value>);

Drop

DROP Function IF EXISTS <function>;

Trigger

Create

DELIMITER $$
CREATE Trigger <trigger>
    AFTER <DELETE | UPDATE | INSERT>
    ON <table>
    FOR EACH ROW
BEGIN
    <statement>;                     -- OLD table, NEW table 사용 가능
END $$
DELIMITER ;

Drop

DROP Trigger IF EXISTS <trigger>;

If/Case/While

Declaration/Initializaion

DECLARE <variable> <type>;      -- declaration

SET <variable> = <value>;       -- set variable

SELECT <column> INTO <variable>
    FROM <table>
    WHERE <condition>;          -- set variable using table

If Statement

IF <condition> THEN
	<statement>;
ELSEIF <condition> THEN
    <statement>;
ELSE
	<statement>;
END IF;

Case Statement

CASE
	WHEN <condition> THEN
		SET <variable> = <value>;
	WHEN <condition> THEN
		SET <variable> = <value>;
	WHEN <condition> THEN
		SET <variable> = <value>;
	WHEN <condition> THEN
		SET <variable> = <value>;
	ELSE
		SET <variable> = <value>;
END CASE;

While Loop

<loop>:
WHILE <condition> DO
    <statement>;     -- ITERATE <loop> : continue, loop 제외 가능
                     -- LEAVE <loop>   : break, loop 제외 가능
END WHILE;

Cursor

DECLARE <row variable> <type>;
DECLARE <end variable> BOOLEAN DEFAULT FALSE;
DECLARE <count variable> INT DEFAULT 0;          -- 변수 설정

DECLARE <cursor> CURSOR FOR
    <select statement>;                          -- cursor 지정

DECLARE CONTINUE HANDLER
    FOR NOT FOUND SET <end variable> = TRUE;     -- loop end 조건

OPEN <cursor>;                                   -- cursor open

<loop>: LOOP                                     -- loop 시작

    FETCH <cursor> INTO <row variable>;          -- table에서 값 받아오기

    IF <end variable> THEN                       -- table 끝까지 오면 loop 빠져나가기
        LEAVE <loop>;
    END IF;

    SET <count variable> = <count variable> + 1; -- table의 row count 세기

END LOOP <loop>;

Prepare

Allocate

PREPARE <prepare> FROM <sql>;                           -- variable을 넣는 곳에는 ?을 넣음

Execute

EXECUTE <prepare> USING @<variable> , @<variable>, ...;

Deallocate

DEALLOCATE PREPARE <prepare>;

Index

Show

SHOW INDEX FROM <table>;               -- 존재하는 index 보기

SHOW TABLE STATUS LIKE <table string>; -- index 상태 보기

Create

CREATE <UNIQUE> INDEX <index>
    ON <table>(<column>) <ASC | DESC>; -- index create

ANALYZE TABLE <table>;                 -- index apply

Drop

DROP INDEX <index> ON <table>;

Operator

>, <,  >=, <=, !=, <>         : 관계 연산자
AND, OR                       : 논리 연산자
BETWEEN <number> AND <number> : 값 사이에 있는지 확인
IN(<element>, <element>, ...) : 포함되어있는지 확인
LIKE                          : 정규식 확인, _(한 문자), %(여러 문자) 사용 가능
IS NULL, IS NOT NULL          : NULL인지 아닌지 확인

Aggregate Function

SUM()           : 합계
AVG()           : 평균
MIN()           : 최소값
MAX()           : 최대값
COUNT()         : 행의 개수
COUNT(DISTINCT) : 행의 개수 (중복은 1개만 인정)

Type

Kind

TINYINT          : 정수                           (1B)
SMALLINT         : 정수                           (2B)
INT              : 정수                           (4B)
BIGINT           : 정수                           (8B)
FLOAT            : 소수                           (4B)
DOUBLE           : 소수                           (8B)
DATE             : 날짜 YYYY-MM-DD                (3B)
TIME             : 시간 HH:MM:SS                  (3B)
DATETIME         : 날짜, 시간 YYYY-MM-DD HH:MM:SS (8B)
CHAR(length)     : 고정 길이 문자형               (1~255B)
VARCHAR(length)  : 가변 길이 문자형               (1~16383B)
TEXT(length)     : 긴 문자형                      (0~65535B)
LONGTEXT(length) : 긴 문자형                      (0~4294967295B)
BLOB             : 이미지, 동영상                 (0~65535B)
LONGBLOB         : 이미지, 동영상                 (0~4294967295B)

Reference

-- 정수에 UNSIGNED | SIGNED 사용 가능
-- CAST(<value> AS <type>)   : 형 변환
-- CONVERT (<value>, <type>) : 형 변환

Reference

AUTO_INCREMENT

CREATE TABLE <table>(
    <column> <type> AUTO_INCREMENT
);                                            -- auto increment 설정

ALTER TABLE <table> AUTO_INCREMENT = <value>; -- 시작값 설정

SET @@auto_increment_increment = <value>;     -- 증가값 설정

DISTINCT

SELECT DISTINCT <column> FROM <table>;

Using Variable

SET @<variable> := <value>;
SET @<variable> = <value>;

UNION

<select statement>
UNION <DISTINCT | ALL>
<select statement>