SQL语句生成时间维度表

转载地址：
https://blog.csdn.net/neweastsun/article/details/43866599

感谢大佬！

mysql中生成时间维度表

       利用mysql常用日期函数生成时间维度表，效率最高，最简单，无需其他的一些工具支持。生成结果示例如下图：

复制下面的运行，就ok，和运行平常的sql语句一样！

  
  
# time span

SET @d0 = "2012-01-01";

SET @d1 = "2012-12-31";



SET @ date = date_sub(@d0, interval 1 day);



# set up the time dimension table

DROP TABLE IF EXISTS time_dimension;

CREATE TABLE `time_dimension` (

`date` date DEFAULT NULL,

`id` int NOT NULL,

`y` smallint DEFAULT NULL,

`m` smallint DEFAULT NULL,

`d` smallint DEFAULT NULL,

`yw` smallint DEFAULT NULL,

`w` smallint DEFAULT NULL,

`q` smallint DEFAULT NULL,

`wd` smallint DEFAULT NULL,

`m_name` char( 10) DEFAULT NULL,

`wd_name` char( 10) DEFAULT NULL,

PRIMARY KEY ( `id`)

);



# populate the table with dates

INSERT INTO time_dimension

SELECT @ date := date_add(@ date, interval 1 day) as date,

# integer ID that allowsimmediate understanding

date_format(@ date, "%Y%m%d") as id,

year(@ date) as y,

month(@ date) as m,

day(@ date) as d,

date_format(@ date, "%x") as yw,

week(@ date, 3) as w,

quarter(@ date) as q,

weekday(@ date)+ 1 as wd,

monthname(@ date) as m_name,

dayname(@ date) as wd_name

FROM T

WHERE date_add(@ date, interval 1 day) <= @d1

ORDER BY date

;
  
  

       神秘的表T，仅仅需要有多于你需要生成日期的记录数即可。思路是从T表选择多行数据，同时生成对应的日期字段。

这里对转载的解释一下：表T可以是任意表，只要记录数比你要生成的天数多就可以了。比如上面的2012-01-01到2012-12-31，只要记录数大于366条就可以！！