MS SQL比较日期？

我有2个日期（日期时间）：

date1 = 2010-12-31 15：13：48.593
date2 = 2010-12-31 00：00：00.000

在同一天，只是时间不同。由于日期1的时间，使用<=比较日期1和日期2不起作用。因此date1 <= date2是错误的，但应为true。我可以仅通过查看年，月和日来比较它们是否相同？它的SQL Server 2008。

谢谢 ：）

SELECT CASE WHEN CAST(date1 AS DATE) <= CAST(date2 AS DATE) ...

应该做你所需要的。

测试用例

WITH dates(date1, date2, date3, date4)
     AS (SELECT CAST('20101231 15:13:48.593' AS DATETIME),
                CAST('20101231 00:00:00.000' AS DATETIME),
                CAST('20101231 15:13:48.593' AS DATETIME),
                CAST('20101231 00:00:00.000' AS DATETIME))
SELECT CASE
         WHEN CAST(date1 AS DATE) <= CAST(date2 AS DATE) THEN 'Y'
         ELSE 'N'
       END AS COMPARISON_WITH_CAST,
       CASE
         WHEN date3 <= date4 THEN 'Y'
         ELSE 'N'
       END AS COMPARISON_WITHOUT_CAST
FROM   dates 

退货

COMPARISON_WITH_CAST   |  COMPARISON_WITHOUT_CAST
Y                         N

使用DATEDIFF日期部分为的函数day。

SELECT ...
FROM ...
WHERE DATEDIFF(day, date1, date2) >= 0

请注意，如果要测试date1<=，date2则需要测试DATEDIFF(day, date1, date2) >= 0，否则可以测试DATEDIFF(day, date2, date1) <= 0。

简单的一线解决方案是

datediff(dd,'2010-12-31 15:13:48.593','2010-12-31 00:00:00.000')=0

datediff(dd,'2010-12-31 15:13:48.593','2010-12-31 00:00:00.000')<=1

datediff(dd,'2010-12-31 15:13:48.593','2010-12-31 00:00:00.000')>=1

您可以尝试使用除“ dd”以外的其他选项

试试这个：

BEGIN

declare @Date1 datetime
declare @Date2 datetime

declare @chkYear int
declare @chkMonth int
declare @chkDay int
declare @chkHour int
declare @chkMinute int
declare @chkSecond int
declare @chkMiliSecond int

set @Date1='2010-12-31 15:13:48.593'
set @Date2='2010-12-31 00:00:00.000'

set @chkYear=datediff(yyyy,@Date1,@Date2)
set @chkMonth=datediff(mm,@Date1,@Date2)
set @chkDay=datediff(dd,@Date1,@Date2)
set @chkHour=datediff(hh,@Date1,@Date2)
set @chkMinute=datediff(mi,@Date1,@Date2)
set @chkSecond=datediff(ss,@Date1,@Date2)
set @chkMiliSecond=datediff(ms,@Date1,@Date2)

if @chkYear=0 AND @chkMonth=0 AND @chkDay=0 AND @chkHour=0 AND @chkMinute=0 AND @chkSecond=0 AND @chkMiliSecond=0
    Begin
        Print 'Both Date is Same'
    end
else
    Begin
        Print 'Both Date is not Same'
    end
End

我总是用DateDiff（day，date1，date2）比较两个日期。

签出以下示例。只需将其复制并在Ms sql服务器中运行即可。另外，尝试将更改日期从12月31日更改为12月30日，然后检查结果

BEGIN

declare @firstDate datetime
declare @secondDate datetime


declare @chkDay int

set @firstDate ='2010-12-31 15:13:48.593'
set @secondDate ='2010-12-31 00:00:00.000'

set @chkDay=Datediff(day,@firstDate ,@secondDate )

if @chkDay=0
    Begin
        Print 'Date is Same'
    end
else
    Begin
        Print 'Date is not Same'
    end
End