text: DROP SCHEMA IF EXISTS LeetCode;
  CREATE SCHEMA LeetCode;
  USE LeetCode;
  
  Create table If Not Exists student (name varchar(50), continent varchar(7));
  Truncate table student;
  insert into student (name, continent) values ('Jane', 'America');
  insert into student (name, continent) values ('Pascal', 'Europe');
  insert into student (name, continent) values ('Xi', 'Asia');
  insert into student (name, continent) values ('Jack', 'America');