03 数据行操作

数据行操作的相关SQL语句（指令）如下：

• 新增数据

  insert into 表名 (列名,列名,列名) values(对应列的值,对应列的值,对应列的值);

  ```sql insert into tb1(name,password) values(‘mufeng’,’123123’); insert into tb1(name,password) values(‘mufeng’,’123123’),(‘alex’,’123’);

insert into tb1 values(‘mufeng’,’123123’),(‘gini’,’123’); — 如果表中只有2列

- [x]  **删**除数据   
```sql
delete from 表名;
delete from 表名 where 条件;

delete from tb1;
delete from tb1 where name="mufeng";
delete from tb1 where name="mufeng" and password="123";
delete from tb1 where id>9;

• 修改数据

  update 表名 set 列名=值;
  update 表名 set 列名=值 where 条件;

  ```sql update tb1 set name=”mufeng”; update tb1 set name=”mufeng” where id=1;

update tb1 set age=age+1; — 整型 update tb1 set age=age+1 where id=2;

update L3 set name=concat(name,”db”); update L3 set name=concat(name,”123”) where id=2; — concat一个函数，可以拼接字符串

- [x]  **查**询数据   
```sql
select * from 表名;
select 列名,列名,列名 from 表名;
select 列名,列名 as 别名,列名 from 表名;
select * from 表名 where 条件;

select * from tb1;
select id,name,age from tb1;
select id,name as N,age, from tb1;
select id,name as N,age, 111 from tb1;
select * from tb1 where id = 1;
select * from tb1 where id > 1;
select * from tb1 where id != 1;
select * from tb1 where name="mufeng" and password="123";