SQL Server中如何对时间字段求和

在SQL Server中，求和操作是一种常见的聚合函数，用于对数值型字段进行求和计算。但是，对于时间字段的求和操作，稍微有些不同。本文将介绍在SQL Server中如何对时间字段进行求和，并提供一个案例代码来加深理解。

sql
SELECT SUM(DATEDIFF(MINUTE, OrderStartTime, OrderEndTime)) AS TotalDuration
FROM Orders
WHERE OrderDate BETWEEN '2022-01-01' AND '2022-12-31'

sql
SELECT DATEADD(DAY, DATEDIFF(DAY, 0, RegistrationDate), 0) AS Date,
       COUNT(*) AS NewUsers
FROM Users
WHERE RegistrationDate BETWEEN '2022-01-01' AND '2022-12-31'
GROUP BY DATEADD(DAY, DATEDIFF(DAY, 0, RegistrationDate), 0)

sql
-- 创建一个示例表Orders
CREATE TABLE Orders
(
    OrderID INT,
    OrderDate DATE,
    OrderStartTime TIME,
    OrderEndTime TIME
)
-- 插入示例数据
INSERT INTO Orders (OrderID, OrderDate, OrderStartTime, OrderEndTime)
VALUES 
    (1, '2022-01-01', '08:00:00', '12:00:00'),
    (2, '2022-01-02', '09:00:00', '11:30:00'),
    (3, '2022-01-03', '10:30:00', '13:30:00')
-- 对订单持续时间进行求和
SELECT SUM(DATEDIFF(MINUTE, OrderStartTime, OrderEndTime)) AS TotalDuration
FROM Orders
-- 输出结果：
-- TotalDuration
-- -------------
-- 360
-- 清理示例数据和表
DROP TABLE Orders