使用遞歸CTE獲取給定月份和月份之間逗號分隔的月份使用遞歸CTE

Question

我們有要求提供2個月和2年作爲輸入的要求。結果應該提供從月份到月份之間所有月份的逗號分隔的月份。

說，我們

From Month is 'Jan' 
From Year is 2011 
To Month is 'Apr' 
To Year is 2011 

所需的輸出

Jan'11,Feb'11,Mar'11,Apr'11 

可以這樣使用遞歸CTE來實現？我們需要使用遞歸CTE來實現這一點。有人能幫我解決這個問題嗎？

Answer 1

試試這個代碼：

--declaration of variables 
declare @frommonth char(3) = 'jan',@fromyear char(4) = 2011, 
     @tomonth char(3) = 'APR', @toyear char(4) = 2011 

declare @output varchar(max) 
declare @f int, @t int 

select --setting from and to month as months after 1900-01-01 
@f = datediff(month, 0, cast('1' +@frommonth+@fromyear as datetime)), 
@t = datediff(month, 0, cast('1' +@tomonth+@toyear as datetime)) 

-- recusive loop 
;with cte as 
(
select @f m 
union all 
select m + 1 from cte 
where m < @t 
) 
select @output = coalesce(@output +',', '') +stuff(convert(varchar(11),dateadd(mm, m, 0), 109), 4, 6, '''') FROM CTE 

select @output 

結果：

Jan'11,Feb'11,Mar'11,Apr'11 

測試在這裏：

http://data.stackexchange.com/stackoverflow/q/114801/declaration-of-variables