show databases;show tables from db_name; show columns from table_name from db_name;show index from talbe_name [from db_name];show status;show variables;show [full] processlist;show table status [from db_name];show grants for user; 除了status,processlist和grants外,其它的都可以带有like wild选项,它可以使用SQL的’%’和’_’字符;s