SQL commands commonly used in database operations

Common sql commands for operating database structure and data

Create database

create database if not exists  数据库名  charset=指定编码

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Using database

use 数据库名

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Create table

create table if not exists 表名(
字段名 类型名,       
id  int,        
birth  date  
);

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Show

显示表(创建表代码)
 show create table 表名字;
显示表结构
 desc 表名;
显示数据库和表
 show 数据库名/表名

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rrree

##Delete

# Add, delete, and modify the data structure check (Basically based on the modified keyword "alter")

删除数据库与表
drop 数据库名/表名

添加列
alter table 表名 add(列名 列类型,列名 列类型);
alter table tab_day1 add(age int,zwjs text);
删除列
alter table 表名 drop 列名;
alter table tab_day1 drop age;

Data addition, deletion and modification query

(这里区别change与modify，change为改变的意思，程度自然比modify大)
修改列名
alter table tab_day1 change 旧列名 新列名 新列类型;
alter table tab_day1 change money salary decimal(10,2);
修改列类型
alter table tab_day1 modify 列名 列新类型;
alter table tab_day1 modify height int;

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