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using group by and maximum

开发者 https://www.devze.com 2023-03-09 22:12 出处:网络
I have a post table and postcontent table. Each time post is edited,an entry is added to postcontent table .

I have a post table and postcontent table.

Each time post is edited,an entry is added to postcontent table .

On each such time a filed called version will be incremented by 1 In the postcontent table.

How can I fetch PostId, fr开发者_运维技巧om post able and [Description] from to postcontent table Where version for each post is maximum Ie group by post id ie i am expecting one raw for each post such that it is the 'maximum of version' for the post


select P.PostID,
       PC.[Description]
from Post as P
inner join 
  (
    select PostID,
           [Description],
           row_number() over(partition by PostID order by [Version] desc) as rn
    from PostContent
  ) as PC
  on P.PostID = PC.PostID
where PC.rn = 1


SELECT 
    p.[PostID],
    pc.[Description]
FROM
    [Post] AS p
INNER JOIN
    [PostContent] AS pc
    on p.PostID = pc.PostID 
WHERE
    pc.[Version] = (SELECT MAX([Version]) FROM PostContent WHERE PostID = p.PostID)


I think u have the PostId in PostContent table as a foreign key and you want to retrive all the postId with their Heighest version .

select max(version),PostId from PostContent groupby PostId
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