mysql 建表,改表结构,插入数据,建立索引,删除索引

创建表

create table employee (employee_id char(6) primary key,name char(8),sex char(2),birthday

date);

create table products (product_id char(2) primary key, name char(20));

察看表结构

describe employ-ee;

describe products;

 

修改表结构

alter table employee modify name char(10);

alter table products modiry name char(30);

向表中添加数据

insert into employee values ('200301','zhangsan','m','1978/5/8');
insert into employee values ('200302','lisi','f','1973/3/20');
insert into employee values ('200303','wangwu','f','1970/10/9');
insert into employee values ('200304','zhaoliu','m','1975/1/18');

 

修改表内容

update employee set employee_id="200310" where name="zhaoliu";

创建索引

建表时创建带索引的表
create table test1 (test1_id char(4),name char(20), index idx_test1(name(10)));

create index idx_employee on employee(name); 用create为name列创建索引

alter table products add index idx_products(name); 用alter为name列创建索引

察看索引

show index from employee;
show index from products;

删除索引

drop index idx_employee on employee;

alter table products drop index idx_products;