要求教师表、课程表和选课表用SQL语句实现

好的，以下是教师表、课程表和选课表的SQL语句实现：

1. 教师表

CREATE TABLE teacher (
  teacher_id INT PRIMARY KEY,
  teacher_name VARCHAR(50) NOT NULL,
  teacher_gender ENUM('male', 'female') NOT NULL,
  teacher_age INT NOT NULL,
  teacher_phone VARCHAR(20) NOT NULL
);

2. 课程表

CREATE TABLE course (
  course_id INT PRIMARY KEY,
  course_name VARCHAR(50) NOT NULL,
  course_teacher_id INT NOT NULL,
  FOREIGN KEY (course_teacher_id) REFERENCES teacher (teacher_id)
);

3. 选课表

CREATE TABLE student_course (
  student_id INT NOT NULL,
  course_id INT NOT NULL,
  PRIMARY KEY (student_id, course_id),
  FOREIGN KEY (student_id) REFERENCES student (student_id),
  FOREIGN KEY (course_id) REFERENCES course (course_id)
);

以上是教师表、课程表和选课表的SQL语句实现，如果您有其他问题，欢迎继续提问。