Common sentences in mysqld/mariadb

Create database if not exists hidb; # create a library if the library does not exist

Show warnings; # View the most recent db alarm

Alter database hidb character set 'utf-8'; # sets the database character set

Drop database testdb; # deleting a library

Show databases like'% db'; # queries database information ending in db

Help show databases; # help

Create table tbl2 (id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE KEY,name VARCHAR (60) NOT NULL); # create a table structure

Create table tbl2 (id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, name VARCHAR (60) NOT NULL,UNIQUE KEY (id,name)); # create table structure

Help desc; # help

Describe city; # query table structure

DESC tbl2; # query table structure

Show engines; # View supported engines

Show table status; # View all table status information

Show table status like 'tablename'\ G; # View single table status information

Show table status where name like 'table'; # View tables that start with table

Show table status where Engine='MyISAM'; # query engine is the table status of MyISAM

Alter table tbl3 ADD gender ENUM ('Fleming recently added M'); # modify the table structure and add enumerated fields

Alter table tbl3 CHANGE id stuid SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY; # modify the field name id to stuid

Alter table tbl3 ADD INDEX (name); # create index

Show INDEXES from tbl3; # View all indexes in the table

Alter table tbl3 drop index id; # Delete the index of the id field

Alter table tbl3 drop primary key id; # Delete the primary key of the id field

Create table tbl4 like mysql.user; # create the tbl4 table and copy the table structure from mysql.user

Create table tbl5 select host,user,passwd from mysql.user; # queries the fields and contents of the mysql.user table and puts them in the newly created table

Create index indexname on tabl5 (id); # create index