2018.6.26

1.第一个返回值是object，第二个返回值是undefined

return后面紧跟换行 系统会给他默认后面加一个；

2。

1. CREATE TABLE student_score(
   name VARCHAR(20),
   course VARCHAR(10),
   score INT(10)
   );
    
   INSERT  INTO  student_score VALUES('张三','语文',81);
   INSERT  INTO  student_score VALUES('张三','数学',75);
   INSERT  INTO  student_score VALUES('李四','语文',76);
   INSERT  INTO  student_score VALUES('李四','数学',90);
   INSERT  INTO  student_score VALUES('王五','语文',81);
   INSERT  INTO  student_score VALUES('王五','数学',100);
   INSERT  INTO  student_score VALUES('王五','英语',90);
    
   SELECT name FROM student_score GROUP BY name HAVING MIN(score)>80
   

3.

package test;
 
public class Client1 {
public static double sumBallHeight(double h, int n) {
if (n == 1)
return h / 2;
else
return sumBallHeight(h / 2, n - 1);
}
 
public static void main(String[] args) {
System.out.println(sumBallHeight(100, 10));
} 

3.

1. 3CREATE TABLE student_score(
2. name VARCHAR(20),
3. course VARCHAR(10),
4. score INT(10)
5. );
7. INSERT INTO student_score VALUES('张三','语文',81);
8. INSERT INTO student_score VALUES('张三','数学',75);
9. INSERT INTO student_score VALUES('李四','语文',76);
10. INSERT INTO student_score VALUES('李四','数学',90);
11. INSERT INTO student_score VALUES('王五','语文',81);
12. INSERT INTO student_score VALUES('王五','数学',100);
13. INSERT INTO student_score VALUES('王五','英语',90);
15. SELECT name FROM student_score GROUP BY name HAVING MIN(score)>80