mysql的yearweek 和 weekofyear函数

1.MySQL 的 YEARWEEK 是获取年份和周数的一个函数，函数形式为 YEARWEEK(date[,mode])

例如 2010-3-14 ，礼拜天

SELECT YEARWEEK('2010-3-14') 返回 11
SELECT YEARWEEK('2010-3-14',1) 返回 10

其中第二个参数是 mode ，具体指的意思如下：

ModeFirst day of weekRangeWeek 1 is the first week …0Sunday0-53with a Sunday in this year1Monday0-53with more than 3 days this year2Sunday1-53with a Sunday in this year3Monday1-53with more than 3 days this year4Sunday0-53with more than 3 days this year5Monday0-53with a Monday in this year6Sunday1-53with more than 3 days this year7Monday1-53with a Monday in this year

2. weekofyear函数是计算出当前日期所在周数，和YEARWEEK('日期',1)的周数一致，但YEARWEEK('日期',1)在小于10的时候，不带0

select WEEKOFYEAR('2016-2-2'); =5