select
SELECT 列名称 FROM 表名称
SELECT * FROM 表名称SELECT LastName,FirstName FROM Persons
insert
INSERT INTO 表名称 VALUES (值1, 值2,....)
INSERT INTO table_name (列1, 列2,...) VALUES (值1, 值2,....)
INSERT INTO Persons VALUES ('Gates', 'Bill', 'Xuanwumen 10', 'Beijing')
INSERT INTO Persons (LastName, Address) VALUES ('Wilson', 'Champs-Elysees')
UPDATE 表名称 SET 列名称 = 新值 WHERE 列名称 = 某值
UPDATE Person SET Address = 'Zhongshan 23', City = 'Nanjing' WHERE LastName = 'Wilson'
delete
DELETE FROM 表名称 WHERE 列名称 = 值
DELETE FROM Person WHERE LastName = 'Wilson'
where
SELECT 列名称 FROM 表名称 WHERE 列 运算符 值
SELECT * FROM Persons WHERE FirstName='Bush'
SELECT * FROM Persons WHERE Year>1965
SELECT * FROM Persons WHERE (FirstName='Thomas' OR FirstName='William')AND LastName='Carter'
desc asc
SELECT Company, OrderNumber FROM Orders ORDER BY Company DESC, OrderNumber ASCcompany降序,ordernumber升序
SQL SELECT DISTINCT 语句
在表中,可能会包含重复值。这并不成问题,不过,有时您也许希望仅仅列出不同(distinct)的值。
关键词 DISTINCT 用于返回唯一不同的值。
语法:
SELECT DISTINCT 列名称 FROM 表名称
SELECT DISTINCT Company FROM Orders