SELECT

选择所有TABLE的列

SELECT * FROM TABLE;

一个列可能会包含多个重复值，有时您也许希望仅仅列出不同（distinct）的值，所以用DISTINCT选择不重复的value的列

DISTINCT

SELECT DISTINCT * FROM TABLE;

根据条件来选择列

SELECT column1, column2, ...
FROM table_name
WHERE condition;

SELECT * FROM Websites WHERE country='CN';

其中ORDER BY后面可以跟不止一个参数ASC升序，DESC降序

SELECT column1, column2, ...
FROM table_name
ORDER BY column1, column2, ... ASC|DESC;

INSERT INTO <table_name> (columns1, columns2, columns 3...)
VALUES (values1, values2,values3,...)

INSERT INTO Websites (name, url, alexa, country)
VALUES ('百度','https://www.baidu.com/','4','CN');

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

UPDATE Websites 
SET alexa='5000', country='USA' 
WHERE name='菜鸟教程';

DELETE FROM table_name
WHERE condition;

DELETE FROM Websites
WHERE name='Facebook' AND country='USA';