MySQL note

1、查看当前所有连接的详细资料:
mysqladmin -uroot -proot -hlocalhost processlist


2、只查看当前连接数(Threads就是连接数).
mysqladmin  -uroot -proot -hlocalhost status

3、null, SubString()
   select * from code_table where "ABC" is not null and SUBSTRING(code_name, 1) > 'D' and code_table_id > 10

4、授权
    1. login:
       mysql -uroot -ppassword

    2.Create Database:
       CREATE DATABASE loyalDB DEFAULT CHARACTER SET UTF8;

    3.Create User "loyal" and Grand Privileges to him with password "pass"
      GRANT ALL PRIVILEGES ON loyalDB.* TO 'loyal'@'localhost' IDENTIFIED BY 'pass' WITH GRANT OPTION;
      GRANT ALL PRIVILEGES ON loyalDB.* TO 'loyal'@'%' IDENTIFIED BY 'pass' WITH GRANT OPTION;

      GRANT ALL PRIVILEGES ON xmldb.* TO 'xmlasia'@'%' IDENTIFIED BY 'xmlasia' WITH GRANT OPTION;