sql-server - 使用 SQL Server 比较日期

Question

我有两个日期(日期时间):

日期1 = 2010-12-31 15:13:48.593
日期2 = 2010-12-31 00:00:00.000

这是同一天，只是时间不同。由于 date1 时间，使用 <= 比较 date1 和 date2 不起作用。所以 date1 <= date2 是错误的，但应该是正确的。我可以只看年、月、日来比较它们吗？这是 SQL Server 2008。

Answer 1

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

应该做你需要的事情。

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 

返回

COMPARISON_WITH_CAST   |  COMPARISON_WITHOUT_CAST
Y                         N