Question

我有一个包含多个日期和主日期（dm）的表。我必须在MS SQL脚本中找到与主日期最接近的日期。在下表中，d1最接近dm。

d1         |d2        |dm        |d3        |d4        |d5
2015.05.06 |2015.10.06|2015.05.05|2015.01.06|2015.06.06|2015.08.06

Answer 1

在SQL Server中，apply可能是更简单的方法：

select t.*, dd.d as closest_date, dd.dname as closest_date_column
from t cross apply
     (select top 1 v.*
      from (values (d1, 'd1'), (d2, 'd2'), (d3, 'd3'), (d4, 'd4')) v(d, dname)
      order by abs(datediff(day, v.d, t.dm))
     ) dd;

Answer 2

试试这个

DECLARE @Tbl TABLE (d1 DATETIME, d2 DATETIME, d3 DATETIME, d4 DATETIME,d5 DATETIME, dm DATETIME)

INSERT INTO @Tbl
SELECT
    '2015.05.06',
    '2015.10.09',   
    '2015.01.06',
    '2015.06.06',
    '2015.08.06',
    '2015.05.05'


SELECT
    *,
    (SELECT TOP 1 A.d
    FROM 
    (
        SELECT ABS(DATEDIFF(DAY, T.dm, T.d1)) a, T.d1 d union all
        SELECT ABS(DATEDIFF(DAY, T.dm, T.d2)) a, T.d2 d union all
        SELECT ABS(DATEDIFF(DAY, T.dm, T.d3)) a, T.d3 d union all
        SELECT ABS(DATEDIFF(DAY, T.dm, T.d4)) a, T.d4 d union all
        SELECT ABS(DATEDIFF(DAY, T.dm, T.d5)) a, T.d5 d
    ) A ORDER BY A.a) ClosestDate
FROM
    @Tbl T

结果

d1          d2          d3          d4          d5          dm          ClosestDate
2015-05-06  2015-10-09  2015-01-06  2015-06-06  2015-08-06  2015-05-05  2015-05-06

找出sql中连续特定日期的最近日期

2 个答案: