数据导入:
Create table If Not Exists Courses (student varchar(255), class varchar(255));
Truncate table Courses;
insert into Courses (student, class) values ('A', 'Math');
insert into Courses (student, class) values ('B', 'English');
insert into Courses (student, class) values ('C', 'Math');
insert into Courses (student, class) values ('D', 'Biology');
insert into Courses (student, class) values ('E', 'Math');
insert into Courses (student, class) values ('F', 'Computer');
insert into Courses (student, class) values ('G', 'Math');
insert into Courses (student, class) values ('H', 'Math');
insert into Courses (student, class) values ('I', 'Math');
表: Courses
+-------------+---------+
| Column Name | Type |
+-------------+---------+
| student | varchar |
| class | varchar |
+-------------+---------+
(student,