行列转换的存储过程
初始图：
效果图：
实现过程：
1：建表、建数据
CREATE TABLE `changeprice` (
`id` bigint(20) NOT NULL auto_increment,
`sid` bigint(20) NOT NULL,
`datecreated` timestamp NOT NULL defaultCURRENT_TIMESTAMP,
`price` varchar(50) NOT NULL,
PRIMARY KEY (`id`)
) ;
插入数据：
(1,1,'2009-05-08','30'),
(2,1,'2009-05-10','50'),
(3,1,'2009-05-11','12'),
(4,1,'2009-05-12','20'),
(5,1,'2009-05-14','50'),
(6,1,'2009-05-15','30'),
(7,3,'2009-05-11','12'),
(8,3,'2009-05-12','30'),
(9,3,'2009-05-14','50'),
(10,3,'2009-05-15','30'),
(11,2,'2009-05-08','30'),
(12,2,'2009-05-09','50'),
(13,2,'2009-05-11','12'),
(14,2,'2009-05-13','20'),
(15,2,'2009-05-14','50'),
(16,2,'2009-05-15','30');
存储过程实现：
CREATE DEFINER=`root`@`localhost` PROCEDURE `test`()
begin
DECLARE done int default 0;
DECLARE strDate DATE;
DECLARE str varCHAR(10000) default '';
DECLARE cur1 CURSOR FOR select DISTINCT(DATE(datecreated)) from changeprice order by datecreated;
DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET done=1;
set done = 0;
open cur1;
REPEAT
FETCH cur1 INTO strDate;
if done <> 1 then
set str=CONCAT(str, ',', 'SUM(if(datecreated=''', strDate, ''', price, 0))', '''', strDate,'''');
end IF;
UNTIL done = 1
END REPEAT;
close cur1;
set @sqlString=CONCAT(' select sid ', str, ' from changeprice group by sid ');
prepare sqlstmt from @sqlString;
execute sqlstmt;
deallocate prepare sqlstmt;
set str='';
end;
编辑器运行 call test();即可
