我有一个像这样的 MySQL 表
CREATE TABLE IF NOT EXISTS `vals` (
`DT` datetime NOT NULL,
`value` INT(11) NOT NULL,
PRIMARY KEY (`DT`)
);
DT 是唯一的日期和时间
数据样本:
INSERT INTO `vals` (`DT`,`value`) VALUES
('2011-02-05 06:05:00', 300),
('2011-02-05 11:05:00', 250),
('2011-02-05 14:35:00', 145),
('2011-02-05 16:45:00', 100),
('2011-02-05 18:50:00', 125),
('2011-02-05 19:25:00', 100),
('2011-02-05 21:10:00', 125),
('2011-02-06 00:30:00', 150);
我需要得到这样的东西:
start|end|value
NULL,'2011-02-05 06:05:00',300
'2011-02-05 06:05:00','2011-02-05 11:05:00',250
'2011-02-05 11:05:00','2011-02-05 14:35:00',145
'2011-02-05 14:35:00','2011-02-05 16:45:00',100
'2011-02-05 16:45:00','2011-02-05 18:50:00',125
'2011-02-05 18:50:00','2011-02-05 19:25:00',100
'2011-02-05 19:25:00','2011-02-05 21:10:00',125
'2011-02-05 21:10:00','2011-02-06 00:30:00',150
'2011-02-06 00:30:00',NULL,NULL
我尝试了以下查询:
SELECT T1.DT AS `start`,T2.DT AS `stop`, T2.value AS value FROM (
SELECT DT FROM vals
) T1
LEFT JOIN (
SELECT DT,value FROM vals
) T2
ON T2.DT > T1.DT ORDER BY T1.DT ASC
但它在结果中返回许多行(29 而不是 9),我找不到任何方法来使用 SQL 来限制它。 MySQL 中可以吗?