问题描述
我有这个查询,我想要一个不使用递归 CTE 的替代查询.任何人都可以编辑和更新查询
I have this query and I want an alternative for this query without using recursive CTE. Can Anybody please edit and update the query
DECLARE @d TABLE(value int ,from_date DATE, to_date DATE);
INSERT @d VALUES (7,'2013-11-05','2013-11-25'),(8,'2013-07-05','2013-12-25'),(7,'2013-02-07','2013-04-14');
WITH cte AS
(SELECT value,from_date
, to_date
, from_date AS mo_from_date
, DATEADD(day, day(from_date)* -1 + 1, from_date) AS bom_date
FROM @d
UNION ALL
SELECT value, from_date
, to_date
, DATEADD(month,1,bom_date)
, DATEADD(month,1,bom_date)
FROM cte
where DATEADD(month,1,mo_from_date) < to_date
)
SELECT value,mo_from_date
, CASE when to_date < DATEADD(month,1,bom_date) THEN
to_date
ELSE
DATEADD(day, -1, DATEADD(month,1,bom_date))
END AS mo_to_date
FROM cte
输出:
value mo_from_date mo_to_date
7 2013-11-05 2013-11-25
8 2013-07-05 2013-07-31
8 2013-08-01 2013-08-31
8 2013-09-01 2013-09-30
8 2013-10-01 2013-10-31
8 2013-11-01 2013-11-30
8 2013-12-01 2013-12-25
9 2013-02-07 2013-02-28
10 2013-03-01 2013-03-31
11 2013-04-01 2013-04-14
我尝试了以下查询,但它不起作用,任何人都可以更新此查询
I have tried below query but its not working,can anybody update this query
;with MonthList as (
select
DATEADD(month, M, '12/1/1899') as 'FirstDay',
dateadd(day, -1, dateadd(month, M + 1, '12/1/1899')) as 'LastDay',
DATEADD(month, M + 1, '12/1/1899') as 'FirstDayNextMonth'
from (
select top 3000 ROW_NUMBER() over (order by s.name) as 'M'
from master..spt_values s) s
)
select
t.value, ml.FirstDay as from_date, ml.LastDay as to_date
from
@d t
inner join MonthList ml
on t.from_date < ml.FirstDayNextMonth
and t.to_date >= ml.FirstDay
推荐答案
这是一种使用内联计数的方法:
This is a method using an inline tally:
DECLARE @d TABLE(value int ,from_date DATE, to_date DATE);
INSERT @d VALUES (7,'2013-11-25','2013-11-05'),(8,'2013-07-25','2013-12-05');
WITH N AS(
SELECT N
FROM (VALUES(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL),(NULL))N(N)),
Tally AS(
SELECT 0 AS I
UNION ALL
SELECT TOP (SELECT MAX(DATEDIFF(MONTH,from_date,to_date)) FROM @d)
ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS I
FROM N N1, N N2) --100 months, add more cross joins for more months
SELECT d.[value],
CASE WHEN DATEADD(DAY,1,EOMONTH(DATEADD(MONTH,T.I,d.from_date),-1)) < d.from_date THEN d.from_date ELSE DATEADD(DAY,1,EOMONTH(DATEADD(MONTH,T.I,d.from_date),-1)) END AS mo_from_date,
CASE WHEN EOMONTH(DATEADD(MONTH,T.I,d.from_date)) > d.to_date THEN d.to_date ELSE DATEADD(MONTH,T.I,d.from_date) END AS mo_to_date
FROM @d d
JOIN Tally T ON DATEDIFF(MONTH,from_date,to_date) >= T.I;
不过,我个人建议你给自己一个日历表,那么问题就简单多了:
I do, personally, however, suggest you get yourself a Calendar Table, then the problem is far more simple:
SELECT d.[value],
CASE WHEN d.from_date > MIN(CT.CalendarDate) THEN d.from_date ELSE MIN(CT.CalendarDate) END AS mo_from_date,
CASE WHEN d.to_date < MAX(CT.CalendarDate) THEN d.to_date ELSE MAX(CT.CalendarDate) END AS mo_to_date
FROM @d d
JOIN dbo.CalendarTable CT ON d.from_date <= CT.CalendarDate --To assumes that the to_date being before the
AND d.to_date >= CT.CalendarDate --the from date is an error.
GROUP BY d.[value],
d.from_date,
d.to_date,
MONTH(CT.CalendarDate),
YEAR(CT.CalendarDate);
两种解决方案都假设 from 日期应该在 to 日期之前之前;即使它在您的数据中似乎不正确.如果您的 from 日期可以是 after 您的 to 日期,我建议您有数据问题,因为如何开始strong> 之后结束?
Both solutions assume that the from date should be before the to date though; even though that it appears to not be true in your data. If your from date can be after your to date, I would suggest you have data issues, as how can something start after it has ended?
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