Question

I have this table

ID    Level    Value
 1     1        10
 1     2        20
 1     3        15
 1     4        18
 2     2        12
 2     1        20
 3     1        50
 3     2        80  

I want find the max level for each id and the value of this max row, Result :

ID    Level    Value
 1     4        18
 2     2        12
 3     2        80  

I don’t want use nested ‘Select’ because my table is too big and nested select slow down my query
Thanks for any help

Answer 1

You can do this with a self-join and a test for null.

SELECT T.*
FROM T
LEFT OUTER JOIN T AS T2
ON T2.ID = T.ID AND T2.[Level] > T.[Level]
WHERE T2.ID IS NULL