Question

Whenever I use the max function I somehow lose all the connection to my other values, so that the row that is printed later doesn’t correlate with the column that I ran max on anymore.

So my table is:

user col1 col2 col3
1    1    2    3
1    3    4    5
2    2    3    1
3    1    1    3
3    2    4    6
4    5    1    5

So if I run

select user, col1, col2, max(col3) as col3
from table
group by user
order by user;

I would get

user col1 col2 col3
1    1    2    5
2    2    3    1
3    1    1    6
4    5    1    5

So the max value of col3 is correct, but it doesn’t get the correct row of that value.

What I want is to get the max value of a column and return that row for each user. If there are multiple max values that it should return all users, even if it has same user id.

Answer 1

Other databases (e.g. MS SQL Server) doesn’t let you mix aggergated values with non-aggregated values, just because you would get the wrong result.

So, if you want non-aggregated values from the record where the maximum value was, join against the table again:

select x.user, y.col1, y.col2, x.col3
from (
  select user, max(col3) as col3
  from table
  group by user
) x
inner join table y on y.user = x.user and y.col3 = x.col3
order by x.user