Sql 选择“最大列值”对应的列值

我有一个人，日期是

yyyymmDD

格式，时间是

hhmmssss

格式

ID    NAME      CREATEDDATE     CREATEDTIME
1      A          20170205       135744300
2      B          20160205       113514368
3      C          20090205       163054942
4      A          20150205       135744301

现在我想在单个查询中获得每个人的计数、最大createddate和相应的createdTIME

我试过了

SELECT NAME, COUNT (ID) AS COUNT, MAX(CREATEDDATE), MAX(CREATEDTIME)
FROM Person

但这给了我每个列的最长日期和最长时间，它没有给我对应于MAX（CREATEDDATE）的CREATEDTIME

e、 g

查询结果为

NAME   COUNT    MAXCREATEDDATE       CORRESPONDINGCREATEDTIME

A        2        20170205             135744301

对应的

CreatedTime

应该是

135744300

---

请帮我做这件事

您可以在内部查询中计算

计数

和

最大值（CREATEDDATE）

，然后返回到您的表中，根据每个人的最大日期获取时间：

select
   R.NAME,
   R.COUNT,
   R.CREATEDDATE,
   P.CREATEDTIME
from
  (
    SELECT NAME, COUNT (ID) AS COUNT, MAX(CREATEDDATE) as CREATEDDATE
    FROM Person
    group by NAME
  ) as R
  left outer join Person as P on P.NAME = R.NAME and P.CREATEDDATE = R.CREATEDDATE

---

您只需使用一个子查询即可做到这一点，该子查询查找每个名称的最大日期并执行内部联接

测试数据

CREATE TABLE #Person (ID int, Name varchar(1), CreatedDate int, CreatedTime int)
INSERT INTO #Person (ID, Name, CreatedDate, CreatedTime)
VALUES
 (1,'A',20170205,135744300)
,(2,'B',20160205,113514368)
,(3,'C',20090205,163054942)
,(4,'A',20150205,135744301)

质疑

结果

Name    CountName   CreatedDate CreatedTime
A       2           20170205    135744300
B       1           20160205    113514368
C       1           20090205    163054942

试试这个答案

SELECT NAME, COUNT(ID) AS COUNT, max(CREATEDDATE), max(CREATEDTIME)
FROM Person
where CREATEDDATE = (select MAX(CREATEDDATE) from Person)
group by NAME

也试试这个

    SELECT DISTINCT
       R.NAME,
       COUNT(1) OVER (PARTITION BY NAME),
       MAX(R.CREATEDDATE) OVER (PARTITION BY NAME ) ,
       MAX(P.CREATEDTIME) OVER (PARTITION BY NAME )
    FROM
        Person

---

还有一个，没有联接或子查询

SELECT NAME, COUNT (ID) AS COUNT
  , MaxCREATEDDATE = MAX(cast(CREATEDDATE as bigint)*1000000000 + CREATEDTIME) /1000000000
  , CorrespTime = MAX(cast(CREATEDDATE as bigint)*1000000000 + CREATEDTIME) %1000000000
FROM Person
GROUP by NAME

---

最后两列是什么数据类型？日期/时间或varchar或int？它们是int。日期和时间是保留格式。这不是OP想要的结果。您的查询将只输出一个创建日期等于所有记录的最大创建日期的人。是的，没错，我希望每个人的最大日期和对应日期time@DineshDB我想，但他的结果确实给出了OP发布的预期结果的例子。我认为现在betterIt仍然是最长时间。OP说的确实是个问题。看我的答案。哇，真是个天才！你能解释一下逻辑吗？我想你已经把这两个都加上了，然后把日期和时间都加上了。第一个CREATEDDATE和CREATEDTIME被包装成单个bigint。当找到max时，将应用整数分割（

/

%

）来取回零件。

SELECT NAME, COUNT (ID) AS COUNT
  , MaxCREATEDDATE = MAX(cast(CREATEDDATE as bigint)*1000000000 + CREATEDTIME) /1000000000
  , CorrespTime = MAX(cast(CREATEDDATE as bigint)*1000000000 + CREATEDTIME) %1000000000
FROM Person
GROUP by NAME

select * from 
(
SELECT *,
       COUNT(1)     OVER (PARTITION BY NAME) as count,
       row_number() OVER (PARTITION BY NAME order by CREATEDDATE desc) as rn
 FROM  Person
) tt
where tt.rn = 1