选择对应于MAX列值的列值

Question

I have a table Person, date is in yyyymmDD format and time is is hhmmssSSS format

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

Now I want to get count of each person and maximum createddate and CORRESPONDING createdTIME in a single query

I tried

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

but this gives me maximum date and maximum time from each column, it does not give me CREATEDTIME corresponding to MAX(CREATEDDATE)

eg

The query results is

NAME   COUNT    MAXCREATEDDATE       CORRESPONDINGCREATEDTIME

A        2        20170205             135744301

The CORRESPONDINGCREATEDTIME should be 135744300

Please help me do it

Answer 1

You could do this simply with a subquery that finds the max date for each Name and perform an inner join.

Test Data

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)

Query

SELECT
a.Name
,b.CtName CountName
,a.CreatedDate
,a.CreatedTime
FROM #Person a
JOIN    (
            SELECT 
            Name
            ,COUNT(Name) CtName
            ,MAX(CreatedDate) MaxDate 
            FROM #Person 
            GROUP BY Name
        ) b
ON a.Name = b.Name
AND a.CreatedDate = b.MaxDate

Result

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

Answer 2

Try this answer,

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

Answer 3

Try this also

    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

Answer 4

One more, no joins or subquery

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

Answer 5

You can calculate count and max(CREATEDDATE) in inner query and then join back to your table to get time according to max date for each person:

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

Answer 6

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