1 插入数据
INSERT INTO 表名[(列名)] VALUES (值)
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(1)简单插入语句
INSERT INTO Student VALUES ('001','陈东','男','1996/6/23','信息管理系')
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(2)多行插入语句
INSERT INTO SC VALUES('001','C001',90),
('001','C002',30),
('001','C005',NULL)
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(3)不按表顺序插入语句
按与表列顺序不同的顺序插入数据
INSERT INTO Student(Sno,Sname,Sex,Dept) VALUES ('001','陈东','男','1996/6/23','信息管理系')
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2 更新数据
UPDATE 表名 SET 列名 = 值
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(1)无条件更新
UPDATE SC SET Grade = Grade+10
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(2)有条件更新
(将“C001”号课程的学分改成5分)
UPDATE Course SET Grade = 5 WHERE Cno = 'C001'
(将计算机系全体学生的成绩加5分)
UPDATE SC SET Grade = Grade+5 FROM SC JOIN Student S ON S.Sno = SC.Sno WHERE Dept = '计算机系'
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3 删除数据
DELETE [TOP (expression) [PERCENT]]
FROM 表名
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(1)无条件删除
DELETE FROM Student
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(2)有条件删除
(删除所有考试成绩不合格的学生的选课记录)
DELETE FROM SC WHERE Grade < 60
(删除Student表中2.5%的行数据)
DELETE TOP (2.5) PERCENT FROM Student