mysql 操作sql语句 操作数据表中的内容/记录

#3. 操作文件中的内容/记录

往哪张表去插入 
insert into 表名指定字段(id,name) 插入要加values(针对前面字段插入)(2,mike);

insert into t1(id,name) values(2,'mike');

insert into t1 values(1,'egon1');

也可以用逗号隔开 同时插入多条记录

insert into t1(id,name) values(1,'egon1'),(2,'egon2'),(3,'egon3');


如果默认不写 按照表字段顺序 插入

增：insert into t1 values(1,'egon1'),(2,'egon2'),(3,'egon3');

查看这张表哪个字段
使用这条命令 前提是切换到t1的数据库，如果在另外一个数据库执行这条sql语句会报错
select id,name from t1;

查看指定数据库的数据表的哪个字段

select id,name from db1.t1;

mysql> insert into t1(id,name) values(2,'mike');
Query OK, 1 row affected (0.00 sec)

mysql> desc t1;
+-------+---------+------+-----+---------+-------+
| Field | Type    | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| id    | int(11) | YES  |     | NULL    |       |
| name  | char(6) | YES  |     | NULL    |       |
+-------+---------+------+-----+---------+-------+
2 rows in set (0.00 sec)

mysql> select id,name from t1;
+------+------+
| id   | name |
+------+------+
|    2 | mike |
+------+------+
1 row in set (0.00 sec)

mysql> select id,name from db1.t1;
+------+------+
| id   | name |
+------+------+
|    2 | mike |
+------+------+
1 row in set (0.00 sec)

* 代表所有字段

查：select * from t1; 

mysql> insert into t1 values(1,'jack'),(3,'ben'),(4,'peter');
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> select * from db1.t1;
+------+-------+
| id   | name  |
+------+-------+
|    2 | mike  |
|    1 | jack  |
|    3 | ben   |
|    4 | peter |
+------+-------+
4 rows in set (0.00 sec)

update t1 set name='sb' ;

最好指定改哪一条记录
改：update t1 set name='sb' where id=2; 

mysql> update db1.t1 set name='alex' where id =1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> desc t1;
+-------+---------+------+-----+---------+-------+
| Field | Type    | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| id    | int(11) | YES  |     | NULL    |       |
| name  | char(6) | YES  |     | NULL    |       |
+-------+---------+------+-----+---------+-------+
2 rows in set (0.06 sec)

mysql> 
mysql> select * from t1;
+------+-------+
| id   | name  |
+------+-------+
|    2 | mike  |
|    1 | alex  |
|    3 | ben   |
|    4 | peter |
+------+-------+
4 rows in set (0.00 sec)

把t1 表删了
delete from t1 
删：delete from t1 where id=1;

mysql> delete from t1 where id=2;
Query OK, 1 row affected (0.00 sec)

mysql> select * from t1;
+------+-------+
| id   | name  |
+------+-------+
|    1 | alex  |
|    3 | ben   |
|    4 | peter |
+------+-------+
3 rows in set (0.00 sec)

delete from t1 把 t1表 所有记录删除掉 表结构还在