非唯一 id 的最后一个条目，其中 X=Y

Question

Please see the above image for rows I would like returned, those highlighted in yellow.

From the picture attached, I would like it to only return id 133766 and 133792 as they end at stage 5 .

I want to pull the last entry for a non-unique id where there could be X amount of entries per non-unique id.

I am not overly experience in SQL, but what I know is;

I could do

SELECT max(stage), id
FROM [dbo].[table] group by id

and this gives me a pretty good starting point. I'd rather sort on the date field, as the "stage" isn't actually an int, I've done that for simplicity here.

So I essentially need to get the last entry (figured out by date) for all non-unique id's where stage doesn't equal X

I feel like it's a really simple, everyday query, but I just can not wrap my head around a simple, efficient way to do it.

Any help is much appreciated.

Answer 1

try this

SELECT * 
FROM(
SELECT Id, Stage, CompletionDate
    ,Row_number() OVER(PARTITION BY ID ORDER BY CompletionDate DESC) AS RN
FROM YourTable
) AS t
WHERE RN = 1 AND Stage = 5;

Answer 2

You could use the window version of MAX

;WITH CTE_DATA AS
(
  SELECT *
  , MAX(stage) OVER (PARTITION BY id) AS max_stage
  FROM [dbo].[table]
)
SELECT *
FROM CTE_DATA
WHERE stage = max_stage
  AND max_stage = 5;

Answer 3

I want to point out that not exists is also a way to approach this:

select t.*
from t
where t.stage = 5 and
      not exists (select 1
                  from t t2
                  where t2.id = t.id and t2.stage > t.stage
                 );

With an index on (id, stage) , you might be surprised at how good the performance is.