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假设我有两个表（SQL Fiddle）。一个记录了不同时间戳的值，另一个指示 ID 和日期时间，以获取最接近的值。使用类似于 Kevin Meade 的NEAREST NEIGHBOR PREFERENCE LOW的内容（但在 SQL Server 2008 中），我想找到最接近目标（人口普查）日期但不在（人口普查）日期之后的指示 ID 的（非空值）。如果存在与人口普查日期匹配的行，请使用该行（除非它具有空值）。如果没有在人口普查日期之前的行，则找到最接近人口普查日期但不在其之前的行并使用该行。

第一张表：

CREATE TABLE Recorded_Vent_Types
    ([PAT_ENC_CSN_ID] int, [RECORDED_TIME] datetime, [MEAS_VALUE] varchar(9));

INSERT INTO Recorded_Vent_Types
    ([PAT_ENC_CSN_ID], [RECORDED_TIME], [MEAS_VALUE])
VALUES
    (11117777,  '2013-06-08 19:36:00.000',  'SIMV/PRVC'),
    (11117777,  '2013-06-08 22:21:00.000',  'PRVC/AC'),
    (11117777,  '2013-06-09 00:10:00.000',  NULL),
    (11117777,  '2013-06-09 03:00:00.000',  'SIMV/PRVC'),
    (11117777,  '2013-06-09 23:59:00.000',  'SIMV/PRVC'),
    (11117777,  '2013-06-10 00:00:00.000',  'NAVA'),
    (11117777,  '2013-06-10 00:20:00.000',  'PS'),
    (11117777,  '2013-06-10 00:25:00.000',  NULL),
    (555999,    '2013-06-08 00:36:00.000',  NULL),
    (555999,    '2013-06-08 22:21:00.000',  'PRVC/AC'),
    (555999,    '2013-06-09 00:10:00.000',  'SIMV/PRVC'),
    (555999,    '2013-06-11 23:15:00.000',  'BIVENT'),
    (555999,    '2013-06-12 00:00:00.000',  NULL),
    (555999,    '2013-06-12 00:20:00.000',  'PS');

第二张表：

CREATE TABLE Census
    ([PAT_ENC_CSN_ID] int, [CENSUS_TIME] datetime);

INSERT INTO Census
    ([PAT_ENC_CSN_ID], [CENSUS_TIME])
VALUES
    (11117777, '2013-06-08 00:00:00'),
    (11117777, '2013-06-09 00:00:00'),
    (11117777, '2013-06-10 00:00:00'),
    (11117777, '2013-06-11 00:00:00'),
    (555999, '2013-06-08 00:00:00'),
    (555999, '2013-06-09 00:00:00'),
    (555999, '2013-06-11 00:00:00'),
    (555999, '2013-06-12 00:00:00');

这是 Meade 先生的 Oracle 代码，用于给定 ID 的一个表中的类似内容：

select *
from claim_history
where claim_id = 1
and status_date =
   (
    select min(status_date)
    from (
          select max(status_date) status_date
          from claim_history
          where claim_id = 1
          and status_date <= sysdate-3
          union all
          select min(status_date)
          from claim_history
          where claim_id = 1
          and status_date > sysdate-3
         )
   )
/

我想要的结果集：

PAT_ENC_CSN_ID    CENSUS_TIME           RECORDED_TIME               MEAS_VALUE
555999      June, 08 2013 00:00:00+0000 June, 08 2013 22:21:00+0000 PRVC/AC
555999      June, 09 2013 00:00:00+0000 June, 08 2013 22:21:00+0000 PRVC/AC
555999      June, 11 2013 00:00:00+0000 June, 09 2013 00:10:00+0000 SIMV/PRVC
555999      June, 12 2013 00:00:00+0000 June, 11 2013 23:15:00+0000 BIVENT
11117777    June, 08 2013 00:00:00+0000 June, 08 2013 19:36:00+0000 SIMV/PRVC
11117777    June, 09 2013 00:00:00+0000 June, 08 2013 22:21:00+0000 PRVC/AC
11117777    June, 10 2013 00:00:00+0000 June, 10 2013 00:00:00+0000 NAVA
11117777    June, 11 2013 00:00:00+0000 June, 10 2013 00:20:00+0000 PS

@Gordon Linoff 让我想到了使用人口普查时间和记录时间之间的日期差异的绝对值。这导致我在这里修改@bobs 解决方案。

SELECT * FROM
    (
    SELECT rvt.PAT_ENC_CSN_ID, CENSUS_TIME, RECORDED_TIME, MEAS_VALUE, ABS(DATEDIFF(s, c.CENSUS_TIME, RECORDED_TIME)) diff,
        ROW_NUMBER() OVER (PARTITION BY rvt.PAT_ENC_CSN_ID, c.CENSUS_TIME ORDER BY ABS(DATEDIFF(s, c.CENSUS_TIME, RECORDED_TIME))) AS SEQUENCE
    FROM Recorded_Vent_Types rvt join Census c on rvt.PAT_ENC_CSN_ID=c.PAT_ENC_CSN_ID
    WHERE MEAS_VALUE IS NOT NULL
    ) as m
WHERE SEQUENCE = 1
ORDER BY PAT_ENC_CSN_ID,CENSUS_TIME
;

但这会返回（绝对）最接近的记录时间，而不会优先考虑人口普查时间之前的记录时间。结果：

PAT_ENC_CSN_ID    CENSUS_TIME           RECORDED_TIME               MEAS_VALUE
555999      June, 08 2013 00:00:00+0000 June, 08 2013 22:21:00+0000 PRVC/AC
555999      June, 09 2013 00:00:00+0000 June, 09 2013 00:10:00+0000 SIMV/PRVC
555999      June, 11 2013 00:00:00+0000 June, 11 2013 23:15:00+0000 BIVENT
555999      June, 12 2013 00:00:00+0000 June, 12 2013 00:20:00+0000 PS
11117777    June, 08 2013 00:00:00+0000 June, 08 2013 19:36:00+0000 SIMV/PRVC
11117777    June, 09 2013 00:00:00+0000 June, 08 2013 22:21:00+0000 PRVC/AC
11117777    June, 10 2013 00:00:00+0000 June, 10 2013 00:00:00+0000 NAVA
11117777    June, 11 2013 00:00:00+0000 June, 10 2013 00:20:00+0000 PS
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1 回答 1

0

您可以在 Oracle 和 SQL Server 中将其作为相关子查询来执行，因为除了前 1 个之外，这几乎是标准 SQL。

这是查询：

select *,
       (select top 1 PAT_ENC_CSN_ID
        from census c
        where c.census_time <= rvt.recorded_time
        order by (case when c.census_time <= rvt.recorded_time then 1 else 0
                  end) desc,
                 (case when c.census_time <= rvt.recorded_time then c.census_time
                  end) desc,
                 c.census_time asc
       ) as nearestVal
from Recorded_Vent_Types rvt

子查询返回一行，基于order by，这是查询的关键。它有三个部分。

第一个将所有人口普查时间放在记录时间之前的开头。第二个按人口普查时间降序排列，第三个按升序排列其余部分。我想将最后两个替换为：

abs(c.census_time - rvt.recorded_time)

因为这在逻辑上就是这样做的。唉，这不起作用，因为abs()在datetime. 然后我必须使用datediff()函数或case语句，它会开始看起来更复杂。

于 2013-06-10T22:00:30.707 回答