SQL Server 2008 通过唯一值获取最后一行

Question

我有一个名为 Events 的 SQL Server 2008 数据库。我只想获取 RadioNumber.

中的每一个最后条目

我的SQL如下：

SELECT 
    MAX(timestamp) AS TimeStamp,
    RadioNumber,
    info,
    RadioNumberInfo,
    success
FROM
    (SELECT TOP 100 PERCENT *
     FROM Events
     WHERE Type = 1
       AND (Info IN (SELECT '1 Frei Funk' FROM Events)
            OR Info IN (SELECT '2 Frei Wache' FROM Events)
            OR Info IN (SELECT '3 Ausgerückt' FROM Events)
            OR Info IN (SELECT '5 Sprechwunsch' FROM Events)
            OR Info IN (SELECT '7 Patient aufg' FROM Events)
            OR Info IN (SELECT '8 Am Transportziel' FROM Events))) AS tmp
GROUP BY 
    tmp.RadioNumber, tmp.Info, tmp.RadioNumberInfo, tmp.Success
ORDER BY 
    Timestamp DESC

结果看起来像这样，红框的行是我要显示的行。

我要改变什么，给他们看？

Answer 1

最简单的方法大概是：

select top (1) with ties . . .
. . .
order by row_number() over (partition by tmp.RadioNumber order by Max(timestamp));

Answer 2

你可以使用关联子查询

SELECT timestamp AS TimeStamp,
       RadioNumber,
       info,
       RadioNumberInfo,
       success
FROM   (SELECT TOP 100 PERCENT *
        FROM   Events
        WHERE  Type = 1
               AND ( Info IN (SELECT '1 Frei Funk'
                              FROM   Events)
                      OR Info IN (SELECT '2 Frei Wache'
                                  FROM   Events)
                      OR Info IN (SELECT '3 Ausgerückt'
                                  FROM   Events)
                      OR Info IN (SELECT '5 Sprechwunsch'
                                  FROM   Events)
                      OR Info IN (SELECT '7 Patient aufg'
                                  FROM   Events)
                      OR Info IN (SELECT '8 Am Transportziel'
                                  FROM   Events) )) AS tmp
where timestamp in (select max(timestamp) from 
FROM   Events
        WHERE  Type = 1
               AND ( Info IN (SELECT '1 Frei Funk'
                              FROM   Events)
                      OR Info IN (SELECT '2 Frei Wache'
                                  FROM   Events)
                      OR Info IN (SELECT '3 Ausgerückt'
                                  FROM   Events)
                      OR Info IN (SELECT '5 Sprechwunsch'
                                  FROM   Events)
                      OR Info IN (SELECT '7 Patient aufg'
                                  FROM   Events)
                      OR Info IN (SELECT '8 Am Transportziel'
                                  FROM   Events) )) tmp1 where radionumber=tmp1.radionumber)

Answer 3

尝试将 ROW_NUMBER 与 PARTITION BY 一起使用：

SELECT
q.*
FROM
(
    SELECT 
      MAX(timestamp) AS TimeStamp
    , RadioNumber
    , info
    , RadioNumberInfo
    , success
    , ROW_NUMBER() OVER (PARTITION BY RadioNumber ORDER BY MAX(timestamp) RN
    FROM
    (
        SELECT TOP 100 PERCENT *
        FROM Events
        WHERE Type = 1
        AND (Info IN (SELECT '1 Frei Funk' FROM Events)
            OR Info IN (SELECT '2 Frei Wache' FROM Events)
            OR Info IN (SELECT '3 Ausgerückt' FROM Events)
            OR Info IN (SELECT '5 Sprechwunsch' FROM Events)
            OR Info IN (SELECT '7 Patient aufg' FROM Events)
            OR Info IN (SELECT '8 Am Transportziel' FROM Events))
    ) AS tmp
    GROUP BY tmp.RadioNumber, tmp.Info, tmp.RadioNumberInfo, tmp.Success
 )q
 WHERE q.RN = 1

以及具有类似数据的示例：

DECLARE @table TABLE
(
    FooStamp DATETIME,
    RadioNumber INT,
    Info VARCHAR(50),
    Success tinyint
)

INSERT INTO @table
(
    FooStamp,
    RadioNumber,
    Info,
    Success
)
VALUES
(
    '2019-03-10 00:27:30', -- FooStamp - DATETIME
    1, -- RadioNumber - INT
    'Info 1', -- Info - VARCHAR
    1 -- Success - tinyint
)
, ('2019-03-10 00:27:31', 1, 'Info 1', 1)
, ('2019-03-10 00:27:32', 1, 'Info 1', 1)
, ('2019-03-10 00:27:33', 1, 'Info 2', 1)
, ('2019-03-10 00:28:38', 2, 'Info 2', 1)
, ('2019-03-10 00:29:38', 3, 'Info 3', 1)

并查询：

SELECT 
q.*
FROM
(
SELECT 
  MAX(t.FooStamp) MaxFooStamp
, t.RadioNumber 
, t.Info
, t.Success
, ROW_NUMBER() OVER (PARTITION BY t.RadioNumber ORDER BY MAX(t.FooStamp)) RN
FROM @table t
GROUP BY   t.RadioNumber
         , t.Info
         , t.Success
)q
WHERE q.RN = 1

输出：

MaxFooStamp                 RadioNumber    Info   Success   RN
2019-10-03 00:27:32.000          1         Info1     1       1
2019-10-03 00:28:38.000          2         Info2     1       1
2019-10-03 00:29:38.000          3         Info3     1       1

Answer 4

感谢您的所有意见和帮助。我通过使用 join 找到了一些帮助。

SELECT a.* 
FROM Events AS a 
INNER JOIN (
    SELECT MAX(a.ID) AS ID, MAX(a.TimeStamp) AS TimeStamp, a.RadioNumber 
    FROM Events AS a 
    WHERE a.Type = 1 
    AND a.Info IN ('1 Frei Funk','2 Frei Wache','3 Ausgerückt','5 Sprechwunsch','7 Patient aufg','8 Am Transportziel') 
GROUP BY a.RadioNumber
) AS b ON b.ID = a.ID 
ORDER BY b.TimeStamp DESC

SQL Server 2008 通过唯一值获取最后一行

SQL Server 2008 get last row by unique value

sql

sql-server

sql-server-2008