[SQL] Basic SQL Statements

데이터베이스 생성

CREATE DATABASE [IF NOT EXISTS] database_name;

 

데이터 여러개 한꺼번에 추가

INSERT INTO MyTable
  (Column1, Column2, Column3)
VALUES
  ('John', 123, 'Lloyds Office'), 
  ('Jane', 124, 'Lloyds Office'), 
  ('Billy', 125, 'London Office'),
  ('Miranda', 126, 'Bristol Office');

 

데이터 수정

UPDATE Customers
SET ContactName = 'Alfred Schmidt', City= 'Frankfurt'
WHERE CustomerID = 1;

 

ALTER/MODIFY COLUMN

ALTER TABLE table_name
ALTER COLUMN column_name datatype;

 

열 삭제

ALTER TABLE table_name
DROP COLUMN column_name;

 

CASE

SELECT OrderID, Quantity,
CASE
    WHEN Quantity > 30 THEN 'The quantity is greater than 30'
    WHEN Quantity = 30 THEN 'The quantity is 30'
    ELSE 'The quantity is under 30'
END AS QuantityText
FROM table_name;