Summary of Commonly Used MySQL Commands in Linux Operating System

 -- Start the database service myslqd start;
-- Enter MySQL -u root -p/mysql -h localhost -u root -p DatabaseName;
-- List database show database;
--Create database create database XXXX;
--Select databaseuse DatabaseName;
--show table;
-- Display the properties of the table show columns from tablename;
--Create database source filename.txt;
--Add a field alter table tablename add column filename datatype;
-- Add multiple fields alter table tablename add column filename1 datatype,add column filename2 datatype;
-- Add a new user grant all On *.* to user@localhost identity by "password";
--Query time select now();
--Query user select user();
--Query the database version select version();
--Query the currently used database select database();
-- Delete the student data in the student_course database: rm -f student_cource/student.*
--Backup database (backup database Apple1)
MySQLdump -u root -p Apple1>C:\Apple1.txt
--Backup table (backup the mytable table in database Apple1)
MySQLdump -u root -p mytable>C:\Apple.txt
-- Create a temporary table (mytable)
create temporary table mytable(id int,address varchar(20),name varchar(20));
-- Before creating a table, first determine whether the table exists in the system. create table if not exists mytable(......);
-- Copy the table structure from the existing table1 to table2
create table table2 select * from table1 where 1<>1;
-- Copy table create table table2 select * from table1;
-- Rename the table name alter table table1 rename as table2;
-- Modify the data type of the column alter table table1 modify ID int unsigned;--Change the type of column ID to int unsigned
alter table table1 change ID SID int unsigned; --Rename column ID to SID and change the type to int unsigned
-- Create index alter table table1 add index Ind_id (ID);
create index ind_ID on tablename (ID);
create unique index ind_id on tablename(ID);
-- Delete index drop index ind_id On table1;
alter table table1 drop index ind_ID;
--Join query characters and multiple columns'
select concat(ID,':',name,'=') from table1
-----------------------The second piece------------------------------------
--Show databaseshow database;
--Show tables in the database show tables;
--Display the data table structure describe tablename;
--Display table records select * from tablename;
--Query users who can operate MySQL select * from user;
--Create databasecreate database databasename
--For example↓
MySQL> create database AA;
---Create table user AA;
mysql> create table table1(ID int auto_increment not null primary key,name char(6),sex char(6),birthday date)
 ---Insert several recordsMySQL> insert into AA values('','张三','男','1971-10-01');
 MySQL> insert into AA values('','刘佳佳','女','1978-10-01');
 --Verify the resultMySQL> select * from AA;
--Change Zhang San's birthday to 1971-01-10
MySQL> update AA set birthday = '1971-01-10' where ID = '1'; 
--Delete recordsMySQL> delete from AA where ID = '1';
--Delete table and librarymysql> drop table tablename;
MySQL> drop database databasename;
--Add universal user-- Format: grant select On database.* to username@localhost identity by 'password'
Username user_1 Password is 123456
--You can log in to this user from any PC and do whatever you want with the databaseMySQL> grant select,insert update,delete on *.* to user_1@"%" identity by "123456";
--Create a user who can only operate the database on this machine. The username is user_2 and the password is 123456
MySQL> grant select,insert update,delete on *.* to user_2@localhost identity by "123456";
--Log in to the database MySQL> -u user_1 -p -h IP address;