[TIL] 22.01.19

Database

• Data Type
• DML - select

SELECT *
FROM tab;

SELECT *
FROM employees;

SELECT last_name, salary
FROM employees;

SELECT hire_date, salary, salary * 12
FROM employees;

SELECT SUM(salary), AVG(salary)
FROM employees;

SELECT * FROM departments;

SELECT DISTINCT department_id
FROM employees;

SELECT salary AS 급여, salary * 12 AS 연봉, first_name "Your Name"
FROM employees;

SELECT '이름은: ' || FIRST_NAME || '성은: ' || LAST_NAME
FROM employees;

SELECT * FROM locations;

SELECT * FROM departments;

DESC employees;

JDBC

1. DB 접속
   • ip, port
   • id, pw
2. DepartmentDAO