在 table 上的两个日期之间动态生成所有月份

Question

我有一个 table 这样的：

NAME	INT_VALUE	START	END
One	100	2013-11-16	2014-11-16

目标是这样输出：

NAME	INT_VALUE	START	END	INTERVAL
One	100	2013-11-16	2014-11-16	11-2013
One	100	2013-11-16	2014-11-16	12-2013
One	100	2013-11-16	2014-11-16	1-2014
One	100	2013-11-16	2014-11-16	2-2014

我已经开始使用它了。但我不太确定如何使用 table 上的开始日期和结束日期来确定开始和结束日期，以计算两者之间的月份列表。

SELECT START, calendar, COUNT(1)
FROM table1 AS t1
    RIGHT JOIN (SELECT row_number() OVER (ORDER BY SEQ4()) AS MONTHS
                ,      TO_DATE(DATEADD(MONTH, MONTHS, '2019-05-01')) AS calendar
                FROM TABLE(GENERATOR(rowcount=>80)))
            ON t1.START = calendar
GROUP BY 1, 2
ORDER BY 2, 1
;

此处的目标是将 int 值与范围内从开始到结束的每个月相关联。

Answer 1

WITH RECURSIVE
cte AS ( SELECT name, int_value, start, `end`, 
                1 rownum, DATE_FORMAT(start, '%m-%Y') `interval`
         FROM source_table
         UNION ALL
         SELECT name, int_value, start, `end`, 
                1 + rownum, DATE_FORMAT(start + INTERVAL rownum MONTH, '%m-%Y')
         FROM cte
         WHERE start + INTERVAL rownum - 1 MONTH < `end` )
         
SELECT name, int_value, start, `end`, `interval`
FROM cte
ORDER BY rownum;

https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=bdd028a7755fdcb8296df2301baeb295

如果您不需要在月份数字前导零，则使用 '%c-%Y' 模式。

Answer 2

所以将 range of numbers 移到它自己的 CTE 中以分离内容，我们现在有一个包含 80 个数字的大列表（可能更大）。

然后我们找到 start/end 之间的月数并加入那么多行。并计算将范围变成 select 部分：

WITH range_of_numbers AS (
    SELECT 
        row_number() OVER (ORDER BY SEQ4())-1 AS rn
    FROM TABLE(GENERATOR(rowcount=>80))
)
SELECT 
    t1.name, 
    t1.int_value, 
    t1.start,
    t1.end,
    DATEADD(MONTH, r.rn, t1.start) as interval
FROM table1 AS t1
JOIN range_of_numbers as r
    ON date_diff('month', t1.START, t1.end) <= between r.rn
ORDER BY 2,1,3;

另一种选择是构建一个远程 DATE table

CREATE TABLE dates AS 
SELECT 
     DATEADD(MONTH, row_number() OVER (ORDER BY SEQ4())-1, '1980-01-01') as month_date
FROM TABLE(GENERATOR(rowcount=>8000))

然后我们用BETWEEN得到(start,end)范围内的包含值会变成：

FROM table1 AS t1
JOIN dates as d
    ON d.month_date BETWEEN t1.START AND t1.end

在 table 上的两个日期之间动态生成所有月份

Generate all months dynamically between two dates on a table

mysql

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