MySQL是一款流行的開源關系型數據庫管理系統，它支持按時間和類型進行分組操作，下面我們來詳細看看。

先看一下表結構：
CREATE TABLE `orders` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
`type` varchar(20) NOT NULL,
`time` datetime NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
插入一些測試數據：
INSERT INTO `orders` (`name`, `type`, `time`) VALUES
('order1', 'type1', '2022-04-01 10:00:00'),
('order2', 'type2', '2022-04-01 11:00:00'),
('order3', 'type1', '2022-04-02 10:00:00'),
('order4', 'type2', '2022-04-02 11:00:00'),
('order5', 'type2', '2022-04-02 12:00:00');

按時間分組

SELECT DATE(time) as date, count(*) as num
FROM orders
GROUP BY DATE(time);
執行結果：
date        num
2022-04-01  2
2022-04-02  3

按類型分組

SELECT type, count(*) as num
FROM orders
GROUP BY type;
執行結果：
type   num
type1  2
type2  3

按時間和類型分組

SELECT type, DATE(time) as date, count(*) as num
FROM orders
GROUP BY type, DATE(time);
執行結果：
type   date        num
type1  2022-04-01  1
type1  2022-04-02  1
type2  2022-04-01  1
type2  2022-04-02  2