SQL：根据两个日期之间的月份为记录创建多行

Question

我的table有如下不同ID和不同开始和结束日期的记录
ID、开始日期、结束日期
1, 2017-02-14, 2018-11-05

我想写一个 SQL without using date dimension table 给出以下输出：基本上每个月在开始和结束日期之间有一个记录.

1, 2017, 02
1, 2017, 03
1, 2017, 04
1, 2017, 05
1, 2017, 06
1, 2017, 07
1, 2017, 08
1, 2017, 09
1, 2017, 10
1, 2017, 11
1, 2017, 12
1, 2018, 01
1, 2018, 02
1, 2018, 03
1, 2018, 04
1, 2018, 05
1, 2018, 06
1, 2018, 07
1, 2018, 09
1, 2018, 10
1, 2018, 11

Answer 1

您必须生成日期并从中选择年份和月份

select distinct year(date),month( date) from
(select  * from (
select 
 date_add('2017-02-14 00:00:00.000', INTERVAL n5.num*10000+n4.num*1000+n3.num*100+n2.num*10+n1.num DAY ) as date 
  from
(select 0 as num
   union all select 1
   union all select 2
   union all select 3
   union all select 4
   union all select 5
   union all select 6
   union all select 7
   union all select 8
   union all select 9) n1,
(select 0 as num
   union all select 1
   union all select 2
   union all select 3
   union all select 4
   union all select 5
   union all select 6
   union all select 7
   union all select 8
   union all select 9) n2,
(select 0 as num
   union all select 1
   union all select 2
   union all select 3
   union all select 4
   union all select 5
   union all select 6
   union all select 7
   union all select 8
   union all select 9) n3,
(select 0 as num
   union all select 1
   union all select 2
   union all select 3
   union all select 4
   union all select 5
   union all select 6
   union all select 7
   union all select 8
   union all select 9) n4,
(select 0 as num
   union all select 1
   union all select 2
   union all select 3
   union all select 4
   union all select 5
   union all select 6
   union all select 7
   union all select 8
   union all select 9) n5
) a
where date >'2017-02-14 00:00:00.000' and date < '2018-11-05'
) as t

Answer 2

请使用以下查询示例：

set @start_date = '2017-02-14';
set @end_date = LAST_DAY('2018-11-05');


WITH RECURSIVE date_range AS
(
select MONTH(@start_date) as month_, YEAR(@start_date) as year_, DATE_ADD(@start_date, INTERVAL 1 MONTH) as next_month_date
UNION
SELECT MONTH(dr.next_month_date) as month_, YEAR(dr.next_month_date) as year_, DATE_ADD(dr.next_month_date, INTERVAL 1 MONTH) as next_month_date
FROM date_range dr
where next_month_date <= @end_date
)
select month_, year_ from date_range 
order by next_month_date desc

Answer 3

这就是我所做的，效果非常好：

-- sample data  
WITH table_data
AS (
    SELECT 1 AS id
        ,cast('2017-08-14' AS DATE) AS start_dt
        ,cast('2018-12-16' AS DATE) AS end_dt

UNION ALL

SELECT 2 AS id
    ,cast('2017-09-14' AS DATE) AS start_dt
    ,cast('2019-01-16' AS DATE) AS end_dt
)

-- find minimum date from the data  
,starting_date (start_date)
AS (
SELECT min(start_dt)
FROM TABLE_DATA
)

--get all months between min and max dates  
,all_dates
AS (
SELECT last_day(add_months(date_trunc('month', start_date), idx * 1)) month_date
FROM starting_date
CROSS JOIN _v_vector_idx
WHERE month_date <= add_months(start_date, abs(months_between((
                    SELECT min(start_dt) FROM TABLE_DATA), (SELECT max(end_dt) FROM TABLE_DATA))) + 1)
ORDER BY month_date
)
SELECT id  
,extract(year FROM month_date)  
,extract(month FROM month_date)  
,td.start_dt  
,td.end_dt  
FROM table_data td  
INNER JOIN all_dates ad  
    ON ad.month_date > td.start_dt  
        AND ad.month_date <= last_day(td.end_dt)  
ORDER BY 1  
    ,2

SQL：根据两个日期之间的月份为记录创建多行

SQL: Create multiple rows for a record based on months between two dates

sql

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