Sql基础

Posted 2020-08-22 高中国流

SELECT 列名称 FROM 表名称

SELECT * FROM 表名称

SELECT DISTINCT Company FROM Orders   去重

SELECT 列名称 FROM 表名称 WHERE 列 运算符 值

=	等于
<>	不等于
>	大于
<	小于
>=	大于等于
<=	小于等于
BETWEEN	在某个范围内
LIKE	搜索某种模式

 

SELECT * FROM Persons WHERE City=‘Beijing‘
SELECT * FROM Persons WHERE FirstName=‘Thomas‘ AND LastName=‘Carter‘

SELECT * FROM Persons WHERE FirstName=‘Thomas‘ OR LastName=‘Carter‘

SELECT Company, OrderNumber FROM Orders ORDER BY Company

INSERT INTO 表名称 VALUES (值1, 值2,....)

INSERT INTO table_name (列1, 列2,...) VALUES (值1, 值2,....)

UPDATE 表名称 SET 列名称 = 新值 WHERE 列名称 = 某值

UPDATE Person SET FirstName = ‘Fred‘ WHERE LastName = ‘Wilson‘

UPDATE Person SET Address = ‘Zhongshan 23‘, City = ‘Nanjing‘ WHERE LastName = ‘Wilson‘

DELETE FROM 表名称 WHERE 列名称 = 值

DELETE FROM Person WHERE LastName = ‘Wilson‘ 

DELETE FROM table_name