Question

这是我的原始数据（匿名）：

id  usage   verified    date
1   4000    Y           2015-03-20
2   5000    N           2015-06-20
3   6000    N           2015-07-20
4   7000    Y           2016-09-20

原始查询：

SELECT
  me.usage,
  mes.verified,
  mes.date
FROM
  Table1 me,
  Table2 mes,
  Table3 m,
  Table4 mp
WHERE
  me.theFk=mes.id
  AND mes.theFk=m.id
  AND m.theFk=mp.id

如何选择最近验证过的和未经过验证的？

所以我会留下：

id  usage   verified    date
1   6000    N           2015-07-20
2   7000    Y           2016-09-20

我正在使用Microsoft SQL Server 2012。

Answer 1

首先，不要使用隐式连接。这已经在十多年前停止了。

其次，接受CTE的功能，in子句和row_number：

with CTE as
(
select 
  me.usage,
  mes.verified,
  mes.date,
  row_number() over (partition by Verified order by Date desc) as CTEOrd
from Table1 me
inner join Table2 mes
  on me.theFK = mes.id
where mes.theFK in
  (
  select m.id
  from Table3 m
  inner join Table4 mp
    on mp.id = m.theFK
  )
)
select CTE.*
from CTE
where CTEOrd = 1

Answer 2

您可以选择按日期排序的TOP 1验证= N，union＆＃39; d，TOP 1按日期排序，验证= Y.

或者在伪SQL中：

SELECT TOP 1 ...fields ...
  FROM ...tables/joins...
  WHERE Verified = 'N'
  ORDER BY Date DESC

UNION 

SELECT TOP 1 ...fields ...
  FROM ...tables/joins...
  WHERE Verified = 'Y'
  ORDER BY Date DESC

Answer 3

drop table #stack2

CREATE TABLE #stack2
    ([id] int, [usage] int, [verified] varchar(1), [date] datetime)
;

INSERT INTO #stack2
    ([id], [usage], [verified], [date])
VALUES
    (1, 4000, 'Y', '2015-03-20 00:00:00'),
    (2, 5000, 'N', '2015-06-20 00:00:00'),
    (3, 6000, 'N', '2015-07-20 00:00:00'),
    (4, 7000, 'Y', '2016-09-20 00:00:00')
;


;with cte as (select verified,max(date) d  from #stack2 group by verified)
select row_number() over( order by s2.[verified]),s2.[usage], s2.[verified], s2.[date] from #stack2 s2 join cte c on c.verified=s2.verified and c.d=s2.date

根据显示的数据，我编写了查询。

对于您的方案，这将是完整的

WITH cte1
     AS (SELECT me.usage,
                mes.verified,
                mes.date
         FROM   Table1 me,
                Table2 mes,
                Table3 m,
                Table4 mp
         WHERE  me.theFk = mes.id
                AND mes.theFk = m.id
                AND m.theFk = mp.id),
     cte
     AS (SELECT verified,
                Max(date) d
         FROM   cte1
         GROUP  BY verified)
SELECT Row_number()
         OVER(
           ORDER BY s2.[verified]),
       s2.[usage],
       s2.[verified],
       s2.[date]
FROM   cte1 s2
       JOIN cte c
         ON c.verified = s2.verified
            AND c.d = s2.date

Answer 4

您可以在下面Without join。

-- Mock data
DECLARE @Tbl TABLE (id INT, usage INT, verified CHAR(1), date DATETIME)
INSERT INTO @Tbl
VALUES
(1,   4000    ,'Y',           '2015-03-20'),
(2,   5000    ,'N',           '2015-06-20'),
(3,   6000    ,'N',           '2015-07-20'),
(4,   7000    ,'Y',           '2016-09-20')


SELECT
    A.id ,
    A.usage ,
    A.verified ,
    A.MaxDate
FROM
(
    SELECT
        id ,
        usage ,
        verified ,
        date,
        MAX(date) OVER (PARTITION BY verified) MaxDate      
    FROM
        @Tbl
) A
WHERE
    A.date = A.MaxDate

结果：

id          usage       verified MaxDate
----------- ----------- -------- ----------
3           6000        N        2015-07-20
4           7000        Y        2016-09-20

Answer 5

CREATE TABLE #Table ( ID INT ,usage INT, verified VARCHAR(10), _date DATE)

INSERT INTO #Table ( ID , usage , verified , _date)
SELECT 1,4000 ,   'Y','2015-03-20' UNION ALL
SELECT 2,   5000 ,   'N' ,'2015-06-20' UNION ALL
SELECT 3,   6000 ,   'N'   ,'2015-07-20' UNION ALL
SELECT 4,   7000 ,   'Y'    ,'2016-09-20'


SELECT ROW_NUMBER() OVER(ORDER BY usage) ID,usage , A.verified , A._date
FROM #Table
JOIN 
(
   SELECT  verified , MAX(_date) _date
   FROM #Table
   GROUP BY verified
) A ON #Table._date = A._date

按日期查找最新记录

5 个答案: