Select语句，但仅返回另一个联接表的最新项

Question

Let's say I'm selecting a candidates details and their work history.

Select candidate.id, candidate.firstname +' '+ candidate.lastname as 'Candidate Name', cwh.dateworked
from candidate
inner join canworkhistory cwh on candidate.id = cwh.candidateid

Now there's multiple records for the dates the candidate has worked but I only want the most recent one.

How do I order these sub-items so that the top 1 is returned in the above query?

Answer 1

You can OUTER APPLY the latest row:

Select candidate.id, candidate.firstname +' '+ candidate.lastname as 'Candidate Name', cwh.dateworked
outer apply (select top 1 * from canworkhistory where candidate.id = canworkhistory.candidateid order by dateworked desc) cwh
from candidate

Answer 2

You can try using window function - row_number()

select * from
(
Select candidate.id, candidate.firstname +' '+ candidate.lastname as 'Candidate Name', cwh.dateworked,row_number() over(partition by candidate.id order by cwh.dateworked desc) as rn
from candidate inner join canworkhistory cwh 
on candidate.id = cwh.candidateid
)X where rn=1

Answer 3

You can use a derived table with group by and max :

Select candidate.id, 
       candidate.firstname +' '+ candidate.lastname as 'Candidate Name', 
       cwh.dateworked
from candidate
inner join (
    select candidateid, max(dateworked) as dateworked
    from canworkhistory
    group by candidateid
) cwh on candidate.id = cwh.candidateid

Answer 4

you can try like below

 with cte as
   (
    Select candidate.id, candidate.firstname +' '+ candidate.lastname 
    as 'Candidate   Name', cwh.dateworked
    from candidate
    inner join canworkhistory cwh on candidate.id = cwh.candidateid
  ) select t.* from cte t where t.dateworked =
                ( select max(dateworked) from canworkhistory t1
                   where t1.candidateid=t.id
                     group by candidateid
                   )

Answer 5

You can try using a CTE as well

;WITH RecentWork
     AS (SELECT
           candidateid
           ,max(dateworked)
         FROM
           canworkhistory
         GROUP  BY
          candidateid)
SELECT
  candidate.id
  ,candidate.firstname + ' ' + candidate.lastname AS 'Candidate Name'
  ,RecentWork.dateworked
FROM
  candidate
  INNER JOIN RecentWork
          ON candidate.id = RecentWork.candidateid