zoukankan      html  css  js  c++  java
  • MySQL增删改查

    1.MySQL安装教程

    创建数据库和创建表请看http://blog.csdn.net/whzhaochao/article/details/12858711

    2.登录MySQL

    选择zhaochao数据库,并查看user表中字段如下:


    3.插入数据

    3.1插入方法一

     insert into user (id,username,userpasswd) values (3,'赵超','zhaochao');

    3.2插入方法二

     insert into user values (4,'赵云','zhaoyun');


    3.3插入方法三

    将自身插入自身
     insert into user select * from user;


    4.删除字段

    4.1删除全部字段

     delete from user;
    mysql> delete from user;
    Query OK, 8 rows affected (0.02 sec)

    4.2删除指定字段

     delete from user where id=4;


    mysql> select * from user;
    +------+----------+------------+
    | id   | username | userpasswd |
    +------+----------+------------+
    |    1 | admin    | admin      |
    |    2 | zhaochao | zhaochao   |
    |    3 | 赵超     | zhaochao   |
    |    4 | 赵云     | zhaoyun    |
    +------+----------+------------+
    4 rows in set (0.00 sec)

    mysql> delete from user where id=4;
    Query OK, 1 row affected (0.03 sec)


    mysql> select * from user;
    +------+----------+------------+
    | id   | username | userpasswd |
    +------+----------+------------+
    |    1 | admin    | admin      |
    |    2 | zhaochao | zhaochao   |
    |    3 | 赵超     | zhaochao   |
    +------+----------+------------+
    3 rows in set (0.00 sec)

    5.修改字段内容

     update user set username='root' where id=1;
    mysql> select * from user;
    +------+----------+------------+
    | id   | username | userpasswd |
    +------+----------+------------+
    |    1 | admin    | admin      |
    |    2 | zhaochao | zhaochao   |
    |    3 | 赵超     | zhaochao   |
    +------+----------+------------+
    3 rows in set (0.00 sec)


    mysql> update user set username='root' where id=1;
    Query OK, 1 row affected (0.03 sec)
    Rows matched: 1  Changed: 1  Warnings: 0


    mysql> select * from user;
    +------+----------+------------+
    | id   | username | userpasswd |
    +------+----------+------------+
    |    1 | root     | admin      |
    |    2 | zhaochao | zhaochao   |
    |    3 | 赵超     | zhaochao   |
    +------+----------+------------+
    3 rows in set (0.00 sec)

    6.查询

    6.1查询一

     select id,username,userpasswd from user;
    mysql> select id,username,userpasswd from user;
    +------+----------+------------+
    | id   | username | userpasswd |
    +------+----------+------------+
    |    1 | root     | admin      |
    |    2 | zhaochao | zhaochao   |
    |    3 | 赵超     | zhaochao   |
    +------+----------+------------+
    3 rows in set (0.00 sec)

    6.2查询二


     select id '用户编号',username '用户名',userpasswd '密码' from user a where a.id=1 ;

    mysql> select id '用户编号',username '用户名',userpasswd '密码' from user a where a.id=1 ;
    +----------+--------+-------+
    | 用户编号 | 用户名 | 密码  |
    +----------+--------+-------+
    |        1 | root   | admin |
    +----------+--------+-------+
    1 row in set (0.00 sec)

    6.1查询三

     select id,username,userpasswd from user limit 1,2;

    mysql> select id,username,userpasswd from user limit 1,2;
    +------+----------+------------+
    | id   | username | userpasswd |
    +------+----------+------------+
    |    2 | zhaochao | zhaochao   |
    |    3 | 赵超     | zhaochao   |
    +------+----------+------------+
    2 rows in set (0.00 sec)


  • 相关阅读:
    be accustomed to doing|actual |acute|adapt |
    By virtue of|sustain|post |scrape off |stretch|access to|take into account of|exploit|hasten|blur |idle|bored her to|account for|accused of|cruelty
    Block to|wreck|Range|Reach|span|chase around|amuse|exploit |instructed
    blast -m1
    qdel
    uname|mv|tar -xzvf|
    Hypothesis Tests for One Population Mean When σ Is Unknown|other
    dll显示调用和隐式调用
    使用预编译头提高编译速度
    NMS过程图示
  • 原文地址:https://www.cnblogs.com/whzhaochao/p/5023488.html
Copyright © 2011-2022 走看看