1、创建数据库CREATE DATABASE _databasename

--创建一个mytest的数据库CREATE DATABASE mytest;--创建一个mytest的数据库并设置默认字符编码CREATE DATABASE mytest DEFAULT CHARACTER SET "utf8";

2、查看已创建的所有数据库SHOW DATABASES

SHOW DATABASES;

3、使用数据库USE _databasename

--使用mytest数据库USE mytest;

4、创建数据表CREATE TABLE _tablename

--创建一个名为user的数据表CREATE TABLE ‘user‘(id SMALLINT,username VARCHAR(20),age TINYINT);

5、查看当前数据库中所有的数据表SHOW TABLES

SHOW TABLES;

6、查看当前数据表中的结构DESC _tablename

--查看hurujiuser表DESC hurujiuser;

 

7、查看创建数据库时的描述SHOW CREATE TABLE _tablename

--查看hurujiuserSHOW CREATE TABLE hurujiuser;

8、插入记录INSERT tablename VALUES

--向user表中插入一条记录INSERT user VALUES("1","huruji","18");--向user表中插入一条记录只包含名字INSERT user(username) VALUES("xie");--向user表中同时插入多条记录INSERT user VALUES(2,,"xie",10),(3,"zhi",12),(4,"huruwa",20);

9、查看数据表中的所有记录SELECT * FROM _tablename

--查看cms_userSELECT * FROM cms_user;

 

10、修改数据表名字 RENAME...

ALTER TABLE hurujiuser RENAME TO xieuser;ALTER TABLE xieuser RENAME AS hurujiuser;ALTER TABLE hurujiuser RENAME xieuser;RENAME TABLE xieuser TO hurujiuser;

11、添加字段ADD

--添加一个字段ALTER TABLE hurujiuser ADD card CHAR(18);--一次添加多个字段ALTER TABLE hurujiuser ADD test CHAR,ADD test2 INT(11),ADD test3 VARCHAR(20);

12、删除字段DROP

--删除一个字段ALTER TABLE hurujiuser DROP test;--一次删除多个字段ALTER TABLE hurujiuser DROP test2,DROP test3;

--同时添加和删除字段ALTER TABLE hurujiuser ADD email VARCHAR(50),DROP age;

13、修改字段MODIFY

ALTER TABLE hurujiuser MODIFY eamil VARCHAR(200) NOT NULL DEFAULT "myuser@qq.com";

14、修改字段位置MODIFY

--将email字段移至addr字段之后ALTER TABLE hurujiuser MODIFY email VARCHAR(200) NOT NULL DEFAULT "myuser@qq.com" AFTER addr;--将username字段移至第一位ALTER TABLE hurujiuser MODIFY username CARCHAR(20) NOT NULL UNIQUE FIRST;

15、添加主键ADD PRIMARY KEY

ALTER TABLE hurujiuser ADD PRIMARY KEY(username);

16、添加唯一ADD UNIQUE

ALTER TABLE hurujiuser ADD UNIQUE(email);

17、为两个字段添加唯一索引ADD UNIQUE INDEX

ALTER TABLE hurujiuser ADD UNIQUE INDEX mul_age_num(age,num);

18、删除唯一索引DROP

ALTER TABLE hurujiuser DROP mul_age_num;

19、删除数据表DROP TABLE _tablename

DROP TABLE hurujiuser;

20、将查询结果插入到新的表中

--将testinsert 中的id，username插入表mytest中INSERT mytest SELECT id,username FROM testinsert;

21、更改数据UPDATE

--将所有记录的age改为15UPDATE hurujiuser SET age=15;--将id=1的记录的age改为2，email为id@qq.comUPDATE hurujiuser SET age=2,email="id@qq.com" WHERE id=1;

22、彻底清空表格TRUNCATE

TRUNCATE TABLE hurujiuser;

23、查询数据SELECT ... FROM ...

--查询所有记录SELECT * FROM hurujiuser;--查询记录中的id和usernameSELECT id username FROM hurujiuser;--查询id=1的记录SELECT * FROM hurujiuser WHERE id=1;--查询id>=6的所有记录SELECT * FROM hurujiuser WHERE id>=6;

24、模糊查询LIKE
%：代表0个、1个或者多个任意字符
_：代表1个任意字符

--搜索名字中含有张字的用户SELECT * FROM cms_user WHERE username LIKE "%张%";--搜索名字中姓张的用户SELECT * FROM cms_user WHERE username LIKE "张%";--搜索姓名为4个字的用户SELECT * FROM cms_user WHERE username LIKE "____";

25、分组查询GROUP BY

SELECT * FROM cms_user GROUP BY proid;

26、显示分组后的详情GROUP_CONCAT

--显示每个组中的姓名SELECT id,sex,GROUP_CONCAT(username) FROM cms_user GROUP BY sex;

27、二次筛选HAVING

SELECT sex,GROUP_CONCAT(username) AS users,COUNT(*) AS totalUsers,MAX(age) AS max_age,SUM(age) AS total_ageFROM cms_user GROUP BY sex HAVING COUNT(*)>2;

28、排序ORDER BY

--升序默认SELECT * FROM cms_user ORDER BY id;SELECT * FROM cms_user ORDER BY id ASC;--降序SELECT * FROM cms_user ORDER BY id DESC;

29、随机显示RAND()

SELECT * FROM cms_user RAND();

30、限制记录LIMIT

--显示前3条SELECT * FROM cms_user LIMIT 3;SELECT * FROM cms_user LIMIT 0,3;--显示4,5,6三条SELECT * FROM cms_user LIMIT 3,3;

31、聚合函数MAX(),MIN(),AVG(),SUM()

SELECT id,sex,age,GROUP_CONCAT(username),COUNT(*) AS totalusers,MAX(age) AS max_age,MIN(age) AS min_age,AvG(age) AS avg_age,SUM(age) AS sum_ageFROM cms_userWHERE id>=1GROUP BY sexHAVING COUNT(*)>=2 ORDER BY age DESC LIMIT 2;

32、内连接查询

SELECT u.id,u.username,u.email,u.sex,p.pronameFROM cms_user AS uINNER JOIN provinces AS p ON u.proid=p.id;SELECT u.id,u.username,p.proNameFROM provinces AS pCROSS JOIN cms_user AS uON p.id=u.proid;SELECT u.id,u.username,u.sex,p.proNameFROM cms_user AS u JOIN provinces AS pON u.proid=p.idWHERE u.sex="男";

33、联合查询UNION

SELECT username FROM employee UNION SELECT username FROM cms_user;

34、子查询

SELECT id username FROM employee WHERE depId IN(SELECT id FROM department);

35、添加外键FOREIGN KEY

CREATE TABLE IF NOT EXISTS employee(id SMALLINT UNSIGNED AUTO_INCREMENT KEY,username VARCHAR(20) NOT NULL UNIQUE,depId TINYINT UNSIGNED,CONSTRAINT emp_fk_dep FOREIGN KEY(depId) REFERENCES department(id))ENGINE=INNODB;ALTER TABLE employee ADD CONSTRAINT emp_fk_dep FROEIGN KEY(depId) REFERENCES department(id);

鼎峰小胡
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35个常用的MYSQL基本操作命令