1.创建表：
| Create Table |
CREATE TABLE `pivot` ( `id` int(11) NOT NULL AUTO_INCREMENT, `salary` double NOT NULL, `year` varchar(4) NOT NULL, `name` varchar(10) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8 |
2.插入数据：
insert into `pivot` (`id`, `salary`, `year`, `name`) values('1','100','2016','tom');
insert into `pivot` (`id`, `salary`, `year`, `name`) values('2','200','2017','tom');
insert into `pivot` (`id`, `salary`, `year`, `name`) values('3','300','2018','tom');
insert into `pivot` (`id`, `salary`, `year`, `name`) values('4','400','2019','tom');
insert into `pivot` (`id`, `salary`, `year`, `name`) values('5','123','2016','nicole');
insert into `pivot` (`id`, `salary`, `year`, `name`) values('6','234','2017','nicole');
insert into `pivot` (`id`, `salary`, `year`, `name`) values('7','345','2018','nicole');
insert into `pivot` (`id`, `salary`, `year`, `name`) values('8','456','2019','nicole');
3.实现行转列方式一：
SELECT `name`,
SUM(salary1) '2016',
SUM(salary2) '2017',
SUM(salary3) '2018',
SUM(salary4) '2019'
FROM (
SELECT `name`,
CASE WHEN `year`= '2016' THEN
salary
END salary1,
CASE WHEN `year`= '2017' THEN
salary
END salary2,
CASE WHEN `year` = '2018' THEN
salary
END salary3,
CASE WHEN `year` = '2019' THEN
salary
END salary4
FROM pivot) t
GROUP BY `name`;
4：实现行转列方式二：
SELECT `name`,
SUM(IF (`year`='2016',salary,NULL)) '2016',
SUM(IF (`year`='2017',salary,NULL)) '2017',
SUM(IF (`year`='2018',salary,NULL))'2018',
SUM(IF (`year`='2019',salary,NULL)) '2019'
FROM `pivot`
GROUP BY `name`;
