一、数据定义
1、创建新数据库：CREATE DATABASE database_name
2、创建新表：CREATE TABLE table_name （column_name datatype,column_name datatype,...）
3、修改数据表：
添加列：ALTER TABLE table_name ADD column_name datatype
删除列：ALTER TABLE table_name DROP COLUMN column_name
修改列：ALTER TABLE table_name ALTER COLUMN column_name datatype
4、删除表：DROP TABLE table_name
二、数据操作
选取数据：SELECT 列名称 FROM 表名称
SELECT * FROM 表名称
过滤重复：SELECT DISTINCT 列名称 FROM 表名称
指定条件：SELECT 列名称 FROM 表名称 WHERE 列 运算符 值
多项条件：SELECT 列名称 FROM 表名称 WHERE 列 运算符 值 AND（OR） 列 运算符 值
排列顺序：SELECT 列名称 FROM 表名称 ORDER BY 列1，列2 DESC（列1升序然后列2倒叙）
插入数据：INSERT INTO 表名称 VALUES (值1, 值2,...)
INSERT INTO table_name (列1, 列2,...) VALUES (值1, 值2,....)
更新数据:UPDATE 表名称 SET 列名称 = 新值 WHERE 列名称 = 某值
删除数据：DELETE FROM 表名称 WHERE 列名称 = 值
三、常用SQL语句范例
选取：SELECT LastName,FirstName FROM Persons
去重：SELECT DISTINCT Company FROM Orders
条件：SELECT * FROM Persons WHERE City=‘Beijing‘
AND与：SELECT * FROM Persons WHERE FirstName=‘Thomas‘ AND LastName=‘Carter‘
OR或：SELECT * FROM Persons WHERE firstname=‘Thomas‘ OR lastname=‘Carter‘
升序：SELECT Company, OrderNumber FROM Orders ORDER BY Company
降序：SELECT Company, OrderNumber FROM Orders ORDER BY Company DESC
插入1：INSERT INTO Persons VALUES (‘Gates‘, ‘Bill‘, ‘Xuanwumen 10‘, ‘Beijing‘)
插入2：INSERT INTO Persons (LastName, Address) VALUES (‘Wilson‘, ‘Champs-Elysees‘)
更新：UPDATE Person SET FirstName = ‘Fred‘ WHERE LastName = ‘Wilson‘
删除：DELETE FROM Person WHERE LastName = ‘Wilson‘
限制条数：SELECT * FROM Persons LIMIT 5
字符检索：SELECT * FROM Persons WHERE City LIKE ‘%BJ%‘
通配符：%：替代一个或多个字符
_：仅替代一个字符；
[ABC]：ABC三者之一；
[^ABC]：除ABC以外
多选条件：SELECT * FROM Persons WHERE LastName IN (‘Adams‘,‘Carter‘)
两者之间：SELECT * FROM Persons WHERE LastName BETWEEN ‘Adams‘ AND ‘Carter‘
指定别名：SELECT po.OrderID, p.* FROM Persons AS p, Product AS po WHERE p.LastName=‘Adams‘ AND p.FirstName=‘John‘
联合查询：SELECT Persons.*, Orders.OrderNo FROM Persons, Orders WHERE Persons.Id_P = Orders.Id_P
JOIN联合：SELECT Persons.*, Orders.OrderNo FROM Persons INNER JOIN Orders ON Persons.Id_P = Orders.Id_P
合并结果：SELECT E_Name FROM Employees_China UNION SELECT E_Name FROM Employees_USA