1.dayofweek函数

功能：统计某天为星期几

dayofweek(date) - Returns the day of the week for date/timestamp (1 = Sunday, 2 = Monday, ..., 7 = Saturday).

dayofweek返回值为：1-7，1 = 星期日, 2 = 星期一, …, 7 = 星期六，从星期日开始

示例：

SELECT dayofweek('2025-07-15');  ---3(星期二)

2.weekday函数

功能：统计某天为星期几

weekday(date) - Returns the day of the week for date/timestamp (0 = Monday, 1 = Tuesday, ..., 6 = Sunday).

weekday返回值为：0-6，0 = 星期一, 1 = 星期二, …, 6= 星期日，从星期一开始
示例：

select weekday('2025-07-15');  ---1(星期二)

3.weekofyear函数

功能统计：某天为某年的第几周

weekofyear(date) - Returns the week of the year of the given date. A week is considered to start on a Monday and week 1 is the first week with >3 days.

select weekofyear('2025-07-15') --29