获取信息：
show databases;
show tables;
show tables from db_name;
show columns from tbl_name;
show index from tbl_name;
show table status;
show table status from db_name;
show create database db_name;
show create table tbl_name;
show variables like '%have%';
show table types;
命令行：
bin/mysql -uroot -ptest
bin/mysql db_name -uroot -ptest
bin/mysql db_name tbl_name -uroot -ptest
bin/mysql --keys db_name tbl_name -uroot -ptest
bin/mysql --status db_name
bin/mysqldump --no-data db_name tbl_name -uroot -ptest