我具有以下数据结构:
表A :
ID | RequestNumber | Date
----+-----------------+-----------
1 | 1 | 2017/09/27
2 | 1 | 2018/06/02
表B :
RequestNumber | Serial | Date
---------------+----------+-----------
1 | 1 | 2017/09/27
1 | 2 | 2017/09/27
1 | 6 | 2018/06/03
1 | 7 | 2018/06/03
1 | 8 | 2018/06/03
我们可以看到,Table A
中与Table B
第一行最接近的日期是2017/09/27,而{{ {1}}
所以...
我需要一个查询,以使Table B
中的每一行与Table A
中的所有行都与Table B
中的记录最接近(这意味着应该向第一条记录返回2条记录并返回3条记录作为第二条记录)
预期结果将是:
Table A
预先感谢
答案 0 :(得分:1)
此查询将执行您想要的操作。它将TableA
与TableB
上的RequestNumber
连接,然后连接到DATEDIFF
和TableB
之间的最小TableA
值的表中,以确保我们仅获得结果中最接近的日期:
SELECT a.ID, a.RequestNumber, b.Serial, b.Date
FROM TableA a
JOIN TableB b ON b.RequestNumber = a.RequestNumber
JOIN (SELECT a.ID AS ID, MIN(ABS(DATEDIFF(day, b.Date, a.Date))) AS days
FROM TableA a
JOIN TableB b ON b.RequestNumber = a.RequestNumber
GROUP BY a.ID) c ON c.ID = a.ID AND c.days = ABS(DATEDIFF(day, b.Date, a.Date))
输出:
ID RequestNumber Serial Date
1 1 1 27/09/2017 09:30:00
1 1 2 27/09/2017 09:30:00
2 1 6 03/06/2018 09:30:00
2 1 7 03/06/2018 09:30:00
2 1 8 03/06/2018 09:30:00
答案 1 :(得分:0)
另一种可能的方法是使用LEFT JOIN和DENSE_RANK()。我假设您想要最接近且大于日期的日期:
CREATE TABLE #TableA (
ID int,
RequestNumber int,
[Date] date
)
CREATE TABLE #TableB (
RequestNumber int,
Serial int,
[Date] date
)
INSERT INTO #TableA (ID, RequestNumber, [Date])
VALUES
(1, 1, '2017-09-27'),
(2, 1, '2018-06-02')
INSERT INTO #TableB (RequestNumber, Serial, [Date])
VALUES
(1, 1, '2017-09-27'),
(1, 2, '2017-09-27'),
(1, 6, '2018-06-03'),
(1, 7, '2018-06-03'),
(1, 8, '2018-06-03'),
(1, 9, '2018-06-05'),
(1, 10, '2018-06-07')
; WITH cte AS (
SELECT
a.ID,
a.RequestNumber,
b.Serial,
b.[Date],
DENSE_RANK() OVER (PARTITION BY a.ID, a.RequestNumber ORDER BY a.ID, a.RequestNumber, b.[Date]) AS rn
FROM #TableA a
LEFT JOIN #TableB b ON (a.RequestNumber = b.RequestNumber) AND (a.[Date] <= b.[Date])
)
SELECT
ID,
RequestNumber,
Serial,
[Date]
FROM cte
WHERE rn = 1
ORDER BY ID, RequestNumber
输出:
ID RequestNumber Serial Date
1 1 1 27/09/2017 00:00:00
1 1 2 27/09/2017 00:00:00
2 1 6 03/06/2018 00:00:00
2 1 7 03/06/2018 00:00:00
2 1 8 03/06/2018 00:00:00
答案 2 :(得分:0)
这将为您提供所需的,尽管我认为您实际上并未为从所需输出中看到的日期正确指定较小的日期术语。
Select * from table B
left join table A
on
B.requestNumber=A.requestNumber
and B.date >=A.Date;
答案 3 :(得分:0)
这是使用横向联接(apply
关键字)的好地方:
select a.*, b.*
from tablea a cross apply
(select top (1) with ties b.*
from tableb b
order by abs(datediff(day, a.date, b.date))
) b;
Here是db <>小提琴。