1.启动和停止服务
一）启动和停止
#启动服务：
$sudo service mysql start
#停止服务：
$sudo service mysql stop
二）创建和选择数据库
【创建数据库】
mysql> create database testdb;
Query OK, row affected (0.01 sec)
mysql> create database testdb default character set 'utf8';
Query OK, 1 row affected (0.00 sec)
status命令查看数据库状态：
mysql> status;
--------------
mysql Ver 14.14 Distrib 5.7., for Linux (i686) using EditLine wrapper Connection id:
Current database:
Current user: root@localhost
SSL: Not in use
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.7. MySQL Community Server (GPL)
Protocol version:
Connection: Localhost via UNIX socket
Server characterset: latin1
Db characterset: latin1
Client characterset: utf8
Conn. characterset: utf8
UNIX socket: /var/run/mysqld/mysqld.sock
Uptime: hours min sec Threads: Questions: Slow queries: Opens: Flush tables: Open tables: Queries per second avg: 0.010
【选择数据库】
mysql> use testdb;
Database changed
【查看当前登录的数据库】
mysql> select database() mydb;
+--------+
| mydb |
+--------+
| testdb |
+--------+
row in set (0.00 sec)
mysql> desc t_users;
+----------+-------------+------+-----+-------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+-------------+------+-----+-------------------+----------------+
| id | int() | NO | PRI | NULL | auto_increment |
| name | varchar() | NO | | NULL | |
| owner | varchar() | NO | | NULL | |
| descinfo | varchar() | YES | | NULL | |
| sex | char() | NO | | | |
| birth | date | YES | | NULL | |
| death | date | YES | | NULL | |
| addtime | datetime | YES | | CURRENT_TIMESTAMP | |
+----------+-------------+------+-----+-------------------+----------------+
rows in set (0.00 sec)
【删除数据库】
mysql> drop database testdb;
Query OK, rows affected (0.00 sec)
【创建用户和分配权限】
mysql> grant all privileges on testdb.* to 'test2'@'localhost' identified by '';
Query OK, rows affected, warning (0.00 sec) mysql> flush privileges;
Query OK, rows affected (0.00 sec) mysql> select host,user,authentication_string from user;
+-----------+---------------+-------------------------------------------+
| host | user | authentication_string |
+-----------+---------------+-------------------------------------------+
| % | root | *9AAE89836D1D658A0BED88FEB96A3DFF84C94D77 |
| % | mysql.session | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| % | mysql.sys | *THISISNOTAVALIDPASSWORDTHATCANBEUSEDHERE |
| localhost | test | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
| localhost | test2 | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 |
+-----------+---------------+-------------------------------------------+
rows in set (0.00 sec)
【创建表】
从源文件引入创建：假设有个sql.txt
DROP TABLE IF EXISTS t_users;
create table t_users (
id int() not null auto_increment,
name varchar() not null comment '姓名',
owner varchar() not null,
descinfo varchar(),
sex char() not null default '',
birth date comment '生日',
death date,
addtime datetime NULL DEFAULT CURRENT_TIMESTAMP COMMENT '创建时间',
primary key (id)
);
然后执行：
mysql> source ./sql.txt;
Query OK, rows affected, warning (0.00 sec) Query OK, rows affected (0.02 sec) mysql> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| t_users |
+------------------+
row in set (0.00 sec) mysql> desc t_users;
+----------+-------------+------+-----+-------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+-------------+------+-----+-------------------+----------------+
| id | int() | NO | PRI | NULL | auto_increment |
| name | varchar() | NO | | NULL | |
| owner | varchar() | NO | | NULL | |
| descinfo | varchar() | YES | | NULL | |
| sex | char() | NO | | | |
| birth | date | YES | | NULL | |
| death | date | YES | | NULL | |
| addtime | datetime | YES | | CURRENT_TIMESTAMP | |
+----------+-------------+------+-----+-------------------+----------------+
rows in set (0.00 sec) mysql> insert into t_users (name,owner,descinfo,birth,death) values ('php webs','test webs','test ok next boooks',curdate(),curdate());
Query OK, row affected (0.01 sec) mysql> select t.* from t_users t;
+----+----------+-----------+---------------------+-----+------------+------------+---------------------+
| id | name | owner | descinfo | sex | birth | death | addtime |
+----+----------+-----------+---------------------+-----+------------+------------+---------------------+
| | php webs | test webs | test ok next boooks | | -- | -- | -- :: |
+----+----------+-----------+---------------------+-----+------------+------------+---------------------+
row in set (0.00 sec)
2.删掉时候用别名
delete t from t_users t where t.title='John';
3.查询及排序
默认asc升序 降序desc
SELECT name, birth FROM pet ORDER BY birth
结果：
查询当前时间和mysql版本函数 curdate() 和 current_date：
mysql> select version(),curdate();
+-----------+------------+
| version() | curdate() |
+-----------+------------+
| 5.7. | -- |
+-----------+------------+
row in set (0.00 sec)
mysql> select version(),current_date;
+-----------+--------------+
| version() | current_date |
+-----------+--------------+
| 5.7. | -- |
+-----------+--------------+
row in set (0.00 sec)
now(): 函数查询当前时间
mysql> select version(),now();
+-----------+---------------------+
| version() | now() |
+-----------+---------------------+
| 5.7. | -- :: |
+-----------+---------------------+
row in set (0.00 sec)
TIMESTAMPDIFF (year,birth,curdate())：日期计算使用 函数计算 查询年龄：
mysql> SELECT name, birth, CURDATE(),TIMESTAMPDIFF(YEAR,birth,CURDATE()) AS age FROM pet;
结果：
is not null 查询不为空的数据：
mysql> select t.* from t_users t where t.title is not null;
+----+------------+--------------+-----------------+
| id | title | author | submission_date |
+----+------------+--------------+-----------------+
| | 学习 PHP | 菜鸟教程 | -- |
| | PHP webs | Doe | -- |
+----+------------+--------------+-----------------+
rows in set (0.00 sec)
day() 和month()函数的使用：查询指定日期的数据：
mysql> select t.* from t_users t where day(t.submission_date)=;
+----+------------+--------------+-----------------+
| id | title | author | submission_date |
+----+------------+--------------+-----------------+
| | 学习 PHP | 菜鸟教程 | -- |
+----+------------+--------------+-----------------+
row in set (0.01 sec) mysql> select t.* from t_users t where month(t.submission_date)=;
+----+------------+--------------+-----------------+
| id | title | author | submission_date |
+----+------------+--------------+-----------------+
| | 学习 PHP | 菜鸟教程 | -- |
| | PHP webs | Doe | -- |
+----+------------+--------------+-----------------+
rows in set (0.00 sec)
mod(n,m) 取余函数的使用；
查询下一个月：
mysql> select mod(month(curdate()),)+ as nextmonth;
+-----------+
| nextmonth |
+-----------+
| |
+-----------+
row in set (0.00 sec)
如：想要查询下一个月过生日的人；
mysql> select t.* from t_users where t.month(birth) = mod(month(curdate()),)+ ;
1 is null 返回false；
1 is not null 返回 true；
mysql> select is not null;
+---------------+
| is not null |
+---------------+
| |
+---------------+
row in set (0.00 sec)
利用count()函数统计数据 以owner分组 group by
mysql> select owner,count(name) from t_users where name like 'C%' group by owner;
+----------+-------------+
| owner | count(name) |
+----------+-------------+
| C webs | |
| GOGGGOOK | |
| GOOOK | |
+----------+-------------+
rows in set (0.00 sec)
max(col)：查询某列的最大值
mysql> select max(id) from t_users;
+---------+
| max(id) |
+---------+
| |
+---------+
row in set (0.00 sec)
【统计每天访问量】
mysql> select t.* from t1 t;
+------+-------+------+
| year | month | day |
+------+-------+------+
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
| | | |
+------+-------+------+
rows in set (0.01 sec) mysql> select year,month,bit_count(bit_or(<<day)) as days from t1 group by year,month;
+------+-------+------+
| year | month | days |
+------+-------+------+
| | | |
| | | |
+------+-------+------+
rows in set (0.00 sec)
4.Mysql使用正则表达式匹配模糊查询 like的使用
Mysql提供了一个标准的SQL模式匹配，和基于扩展的正则表达式的模式匹配Unix工具（如vi,grep,sed)一样。
SQL模式匹配可以使用：
“_“来匹配任意单个字符，
”％“可以用来匹配任意数量（包含0个字符）的字符。
在MySQL中，SQL模式匹配的大小写默认是不敏感的，以下有一些例子，当你在使用SQL模式时，不要使用＝或<>，而是使用LIKE或NOTLIKE。
要找到P%开头的名字：
mysql> select t.* from t_users t where t.title like 'P%'
-> ;
+----+----------+--------+-----------------+
| id | title | author | submission_date |
+----+----------+--------+-----------------+
| | PHP webs | Doe | -- |
+----+----------+--------+-----------------+
row in set (0.00 sec)
查询以%P结尾的名字：
mysql> select t.* from t_users t where t.title like '%PHP';
+----+------------+--------------+-----------------+
| id | title | author | submission_date |
+----+------------+--------------+-----------------+
| | 学习 PHP | 菜鸟教程 | -- |
+----+------------+--------------+-----------------+
row in set (0.00 sec)
使用“_”匹配 4个字符的名字：
mysql> select t.* from t_users t where t.title like '____';
+----+-------+--------+-----------------+
| id | title | author | submission_date |
+----+-------+--------+-----------------+
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
+----+-------+--------+-----------------+
rows in set (0.00 sec)
5.利用正则表达式REGEXP 和 NOT REGEXP
MySQL提供的其他模式匹配类型是使用扩展的正则表达式，当你使用这个类型来测试一个匹配，
要使用REGEXP和NOT REGEXP操作（或者RLIKE和NOT RLIKE，他们是同意詞）。
下面的列表描述了一些扩展正则表达式的特征：
"."匹配任意单个字符.
[a-z]:单个字符匹配类"[...]"匹配括号里的任意字符，例如，"[abc]"匹配"a","b",或"c",要指定字符范围，可以使用"-",
例如，[a-z] 匹配任意字母，而[0-9]匹配任意数字。
"*" 匹配0个或多个在它前面的东西。例如，"x*" 匹配任意个x字符，"[0-9]*"匹配任意个数字，".*"匹配任意个字符。
一个REGEXP模式匹配成功的条件是，模式在测试值中的任意地方匹配即可。
（这与LIKE模式匹配不同，LIKE模式匹配成功需要匹配整个值）。
"^" 开头作为模式匹配或用
"$" 作为模式的结尾。
为了验证扩展的正则表达式是如何工作的，在这使用REGEXP对前面使用LIKE查询进行重写。
查询以P开头：
mysql> select * from t_users where title regexp '^P';
+----+----------+--------+-----------------+
| id | title | author | submission_date |
+----+----------+--------+-----------------+
| | PHP webs | Doe | -- |
+----+----------+--------+-----------------+
row in set (0.00 sec)
查询以s结尾：
mysql> select * from t_users where title regexp 's$';
+----+----------+--------+-----------------+
| id | title | author | submission_date |
+----+----------+--------+-----------------+
| | PHP webs | Doe | -- |
+----+----------+--------+-----------------+
row in set (0.00 sec)
查询title包含e字符的：
mysql> select * from t_users where title regexp 'e';
+----+------------+----------+-----------------+
| id | title | author | submission_date |
+----+------------+----------+-----------------+
| | PHP webs | Doe | -- |
| | nexJohn | Doe | -- |
| | nexJohn123 | Doe baok | -- |
+----+------------+----------+-----------------+
rows in set (0.00 sec)
利用...匹配查询4个字符的名称：如查询以J开头的 并且是...表示三个字符
如：要找到只包含3个字符的名字，使用“^"和“$"来匹配名字的开头和结尾，且放3个“."在中间
mysql> select * from t_users where title regexp '^J...$';
+----+-------+--------+-----------------+
| id | title | author | submission_date |
+----+-------+--------+-----------------+
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
+----+-------+--------+-----------------+
rows in set (0.00 sec)
利用{n} ；n表示重复次数来替换上面的语句查询：
mysql> select * from t_users where title regexp '^.{4}$';
+----+-------+--------+-----------------+
| id | title | author | submission_date |
+----+-------+--------+-----------------+
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
| | John | Doe | -- |
+----+-------+--------+-----------------+
rows in set (0.00 sec)