SQL구문 기초

(해당 수업은 postgresql과 pgAdmin을 이용한다.)

 

 

SELECT ->  SELECT column FROM table; 

 

DISTINCT -> SELECT DISTINCT column FROM table; 

//중복을 허용하지 않고 추출

 

COUNT -> SELECT COUNT(*) FROM payment;

//조건에 해당하는 행의 갯수

 

SELECT WHERE  

->  SELECT name FROM table WHERE name='David';

-> SELECT name, choice FROM table WHERE name='David' AND choice='Red'

 

ORDER BY

-> SELECT column-1, column-2 FROM table ORDER BY column_, ASC

//오름차순, 내림차순으로 정렬

 

LIMIT -> SELECT * FROM payment ORDER BY payment_date DESC LIMIT 5; 

// 한정된 숫자만 추출 

 

BETWEEN ->  SELECT * FROM payment WHERE amount BETEEN 8 AND 9;

 

IN -> SELECT color FROM table WHERE color IN('red', 'blue', 'green');

 

LIKE -> SELECT COUNT(*) FROM customer WHERE first_name LIKE 'J%' AND last_name LIKE 'S%' ;