Question

我有一个由2列组成的表：id和month_year

id  month_year 

1   Dec 2016
2   Jan 2017
3   Feb 2017
4   Mar 2017
.
...
.......

我需要一个包含日期格式的结果，如下所示

        id  month_year 

        1   2016-12-01
        2   2017-01-01
        3   2017-02-01
        4   2017-03-01
        ..
        ....
        ......

      (We can assume the date to be 1st)

我可以通过硬编码来实现它

 SELECT id , case when a.month_year = 'Dec 2016' THEN 
 STR_TO_DATE('01/12/2016','%d/%m/%Y')
 when a.month_year = 'Jan 2017' THEN 
 STR_TO_DATE('01/1/2017','%d/%m/%Y')
 when a.month_year = 'Feb 2017' THEN  
STR_TO_DATE('01/2/2017','%d/%m/%Y')
 when a.month_year = 'Mar 2017' THEN  
STR_TO_DATE('01/3/2017','%d/%m/%Y')
 end as month_year from [table] a

但是当新数据到来时，我想要没有哈希它这个查询不会工作......我可以继续进一步吗？

Answer 1

E.g：

SELECT STR_TO_DATE(CONCAT('Dec 2016','01'),'%b %Y %d');
+-------------------------------------------------+
| STR_TO_DATE(CONCAT('Dec 2016','01'),'%b %Y %d') |
+-------------------------------------------------+
| 2016-12-01                                      |
+-------------------------------------------------+

Answer 2

SELECT DATE_FORMAT(STR_TO_DATE('Dec 2017','%M %Y'), '01/%m/%Y');

输出：01/12/2017

将缩写字符串格式的日期转换为mysql中的日期格式

2 个答案: