📍SQL 문법

• CREATE (테이블 생성)

  • CREATE TABLE student ( 칼럼명 타입 조건(not null 등), 칼럼명 타입 조건(not null 등), 칼럼명 타입 조건(not null 등), PRIMARY KEY ~~ );

• INSERT (삽입)

  • INSERT INTO student values (테이블에 맞는 데이터 양식);

• UPDATE (수정)

  • UPDATE 테이블명 SET 컬럼=값 WHERE 조건;

• DELETE (삭제)

  • DELETE FROM 테이블 WHERE 조건;

• SELECT (조회)

  • SELECT * FROM student;
  • SELECT age, name FROM student;

• SELECT 문법 순서

  1. SELECT
  2. FROM
  3. WHERE
  4. GROUP BY
  5. HAVING
  6. ORDER BY
  • 실행순서는 2>3>4>5>1>6

• WHERE (조건)

  • SELECT * FROM student WHERE id=1;
  • SELECT * FROM student WHERE name=’유%’; (like 조건)

• LIMIT (조회 결과 행수의 제한)

  • SELECT * FROME student limit 1;

• GROUP BY (그룹화)

  • SELECT age FROM student GROUP BY age;

• ORDER BY (정렬)

  • SELECT age FROM student ORDER BY DESC; (오름차순은 ASC)

• DISTINCT (중복행 제거)

  • SELECT DISTINCT name FROM student;

• ALIAS (별칭)

  • SELECT age ‘나이’ FROM student WHERE id = 3;