Question

我想要获得一年中的具体日子。

这是我到现在为止所尝试的： -

-- Declare few variables
DECLARE @Currentdate AS DATETIME
DECLARE @DueDate AS DATETIME
DECLARE @NewDate AS DATETIME

-- Set the variables properly, just for testing
SET @Currentdate = GETDATE()                
SET @DueDate = DATEADD(MONTH, 2, DATEADD(YEAR, 1, @Currentdate))

-- Check the output
SELECT @Currentdate     -- 2013-09-30 00:00:00.000
SELECT @DueDate         -- 2014-11-30 00:00:00.000

所以，我想根据@NewDate年获得@Currentdate。为此，我尝试了： -

SELECT @NewDate = DATEADD(DAY, DAY(DATEDIFF(day, 1, @DueDate)), DATEADD(MONTH, DATEDIFF(MONTH, 0, @Currentdate), 0))
SELECT @NewDate    -- 2013-09-30 00:00:00.000

但它没有奏效。：（

我的预期结果如下：

-- 2013-11-30 00:00:00.000
-- Having the due date month and date same, but the year as current date one.

感谢任何帮助！

更新

很抱歉我创造了所有的困惑。用简单的话说我的问题是： -

我想得到一个新的日期变量，其日期和月份与@DueDate变量相同，但是@Currentdate变量中给出的年份。

我希望这会让事情变得清晰。

Answer 1

如果问题是“考虑到我在一个变量中有一个特定的日期时间值，我可以将另一个变量设置为同一天和月，但在当前年份”，那么答案将是：

declare @DueDate datetime
declare @NewDate datetime

set @DueDate = '20141130'
--Need to set @NewDate to the same month and day in the current year

set @NewDate = DATEADD(year,
       --Here's how you work out the offset
       DATEPART(year,CURRENT_TIMESTAMP) - DATEPART(year,@DueDate),
    @DueDate)

select @DueDate,@NewDate

我想得到一个新的日期变量，其日期和月份与@DueDate变量相同，但是@Currentdate变量中给出的年份。

嗯，这只是上面的查询，只需一个调整：

set @NewDate = DATEADD(year,
       --Here's how you work out the offset
       DATEPART(year,@Currentdate) - DATEPART(year,@DueDate),
    @DueDate)

Answer 2

试试这个吗？

DECLARE @Currentdate AS DATETIME
DECLARE @DueDate AS DATETIME

-- Set the variables properly, just for testing
SET @Currentdate = GETDATE()                
SET @DueDate = DATEADD(MONTH, 2, DATEADD(YEAR, 1, 
             DateAdd(day, datediff(day, 0, @currentDate), 0)))

-- Check the output
SELECT @Currentdate     -- 2013-09-30 18:32:35.310
SELECT @DueDate

使用DateAdd(day, datediff(day, 0, @DateTime), 0)剥离时间部分。您还应该查看此SO Question/answer。

Answer 3

试试这个：

CAST(CAST(  -- cast INT to VARCHAR and then to DATE
    YEAR(GETDATE()) * 10000 + MONTH(@DueDate) * 100 + DAY(@DueDate) -- convert current year + @DueDate's month and year parts to YYYYMMDD integer representation
    + CASE  -- change 29th of February to 28th if current year is a non-leap year
        WHEN MONTH(@DueDate) = 2 AND DAY(@DueDate) = 29 AND ((YEAR(GETDATE()) % 4 = 0 AND YEAR(GETDATE()) % 100 <> 0) OR YEAR(GETDATE()) % 400 = 0) THEN 0
        ELSE -1
    END
AS VARCHAR(8)) AS DATE)

获取Sql Server中一年的特定日期

3 个答案: