MySQL裏獲取當前week、month、quarter，以及date()，date_format()和str_to_date()，DATEDIFF()操作

查詢某年的數據

• 查詢某年的數據

 select * from oa_item_info where created like '2018-%';

select * from oa_item_info where left(created,4)='2018';

select * from oa_item_info where year(created)='2018';

• 今年的數據：

select * from oa_item_info where year(created)=year(now());

• 上一年的數據：

select * from oa_item_info where year(created)=year(date_sub(now(),interval 1 year));

查詢某季度的數據

select QUARTER(created)  as quartername ,created from oa_item_info ;

先看一下quarter函數返回的數據，第一列是quartername,第二列是created

1-3月返回1，4-6月返回2,7到9月返回3,10到12月返回4

並不是搜索本季度的數據：

select * from oa_item_info where QUARTER(created)=QUARTER(now());

這條sql語句返回的是所有年份，當前季度的數據，比如現在是4月，會把所有年份4到6月的數據都檢索出來

搜索本季度的數據：

加上本年的限制條件

 select * from oa_item_info where QUARTER(created)=QUARTER(now()) and year(created)=year(now());

查詢某月的數據

 select month(created) as monthname,created from oa_item_info；

看一下返回數據：第一列是monthname,第二列是created

所有年份2月的數據

 select * from oa_item_info where month(created)=2；

加上年份的限定條件就可以了

查詢某周的數據

select week(created) as weekname,created from oa_item_info ;

看一下返回數據：第一列是weekname,第二列是created

返回的是一年中的第幾周

本週的數據：

 select  created   from oa_item_info where week(created)=week(now()) and year(created)=year(now());

select * from oa_item_info where YEARWEEK(date_format(created,'%Y-%m-%d')) = YEARWEEK(now()) ；

看一下week和yearweek的區別：

數據庫中加入兩條週數一致的日期：

看一下yearweek的返回值：

看一下搜索結果：

select  created   from oa_item_info where week(created)=week(now());

week把兩條年份不一樣的都搜出來了

 select created  from oa_item_info where YEARWEEK(date_format(created,'%Y-%m-%d')) = YEARWEEK(now()) ;

select created  from oa_item_info where YEARWEEK(created) = YEARWEEK(now()) ;

不用date_format函數也可以

yearweek只搜出了今天的

---

未完