text: show databases;
  drop database tmp; 
  create database tmp;
  use tmp;
  show tables;
  
  select * from city;
  select * from city_streets;
  select * from mayor;
  select * from street;
  
  select * from user;
  
  
  show databases;
  
  show tables;
  
  select * from sina_status_raw_data_table 
  where id >250
  order by id desc;
  select * from sina_data_atype;
  