创建stu_score表如下图：

查询结果如下图

sql语句

select name as ‘姓名’，
max(case course when ‘高数’ then score else 0 end) as ‘高数’，
max(case course when ‘英语’ then score else 0 end) as ‘英语’,
max(case course when ‘c语言’ then score else 0 end) as ‘c语言’
from str_score group by name

• 如果没有group by name 则查询 出来的只有一条数据。如图
• 

#define _CRT_SECURE_NO_WARNINGS
#include<stdlib.h>
#include<stdio.h>
#include<string.h>

//把三行四列输出为四行三列
void main(void)
{
	int s[3][4]={{1,1,1,1},{2,2,2,2},{3,3,3,3}},i,j;
	int *p = s[0];//指向0的位置
	printf("下列是三行四列的输出\r\n");
	for (i = 0; i < 12; i++)
	{
		printf("%d ",*(p+i));
		if((i+1) % 4 == 0)//如果是行输出够了四个就换行
		{
			printf("\r\n");
		}
	}
	printf("下列是四行三列!!\n");
	for (i = 0; i < 4; i++)//四行
	{
		for (j = 0; j < 3; j++)//三列
		{
			printf("%d ",*(p+i+j*4));
		}
		printf("\r\n");
	}
	system("pause");
}

转载于:https://www.cnblogs.com/butterflybay/p/11460195.html