DML语句(insert,update ,delete,select)–插入语句select * from student;–单独的插入一条语句insert into student(sno,sname,sex,address,cardid)values(2,’张三’,’男’,’长沙’,’12313′)update student set sex=’女’rollback;–插入的时候要注意的地方(1)要插入的列名的个数必须和值的个数匹配(2)当有约束的情况下面要考虑约束(check，default,foreign key,unique)(3) 数据类型(考虑完整性约束(实体完整性，域完整性，引用完整性，自定义完整性))(4)在SQL server里面，当有标识列存在的情况下，我们不能显示的给这个标识列插入值–考虑默认约束的情况下面insert into student(sno,sname,sex,cardid)values(2,’张三’,’男’,’12322′)insert into studentvalues(3,’李四’,’女’,default,’23’)–一次性插入多行数据–在SQL SERVER 里面/*–自己输入的值insert into studentselect 110,’张三’,’男’,getdate(),95031 unionselect 111,’张2′,’男’,getdate(),95031 unionselect 112,’张3′,’男’,getdate(),95031 unionselect 113,’张4′,’男’,getdate(),95031–创建表的同时插入另外一张表里面的数据(表不存在的情况下)select * into newStudent from student;–同时只能执行一次select * from newStudent;truncate table newStudent;drop table newStudent;–表已经存在的情况下insert into newStudent select * from student;–只复制表结构不要复制数据select * into newStudent from student where 1=0;–我们在创建表的同时添加一个字段，在这个字段上面添加标识列select identity(int,1,1) as sno,sname,ssex into newStudent from student;select * from newStudent;*/select * from student;–在oracle里面一次性插入多行记录insert into studentselect 110,’张三’,’男’,’长沙’,’95031′ from dual unionselect 111,’张2′,’男’,’长沙’,’95032′ from dual unionselect 112,’张3′,’男’,’长沙’,’95033′ from dual unionselect 113,’张4′,’男’,’长沙’,’95034′ from dualselect * into newStudent from student; –在oracle里面错误create table newStudent(sno int primary key,sname varchar2(20))select * from newStudent;–往已经存在的表中插入另外一张表中的数据insert into newStudent select sno,sname from student;commit;select * from student;–更新语句update 表名 set 字段名=值 where 条件update student set sname = ‘王五’ where sno =111;rollback;–删除语句delete from student where sno =111;delete cardid from student;–不能删除指定列的值–删除表中的所有记录truncate table student;–相当于delete from student;truncate table tt1;select * from student;insert into studentvalues(1,’张三’,’男’,default,’111′)create table tt(sno int primary key,sname varchar2(20))insert into tt select sno,sname from student;select * from tt;truncate table tt;–查询selectselect 12+12 from dual;–select 执行顺序我们不能随意更改selectfromwheregroup byhavingorder by
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