How to Find the Record in a Table That Contains the Maximum Value

SQL select only rows with max value on a column

At first glance...

All you need is a GROUP BY clause with the MAX aggregate function:

SELECT id, MAX(rev)
FROM YourTable
GROUP BY id

It's never that simple, is it?

I just noticed you need the content column as well.

This is a very common question in SQL: find the whole data for the row with some max value in a column per some group identifier. I heard that a lot during my career. Actually, it was one the questions I answered in my current job's technical interview.

It is, actually, so common that Stack Overflow community has created a single tag just to deal with questions like that: greatest-n-per-group.

Basically, you have two approaches to solve that problem:

Joining with simple group-identifier, max-value-in-group Sub-query

In this approach, you first find the group-identifier, max-value-in-group (already solved above) in a sub-query. Then you join your table to the sub-query with equality on both group-identifier and max-value-in-group:

SELECT a.id, a.rev, a.contents
FROM YourTable a
INNER JOIN (
    SELECT id, MAX(rev) rev
    FROM YourTable
    GROUP BY id
) b ON a.id = b.id AND a.rev = b.rev

Left Joining with self, tweaking join conditions and filters

In this approach, you left join the table with itself. Equality goes in the group-identifier. Then, 2 smart moves:

1. The second join condition is having left side value less than right value
2. When you do step 1, the row(s) that actually have the max value will have NULL in the right side (it's a LEFT JOIN, remember?). Then, we filter the joined result, showing only the rows where the right side is NULL.

So you end up with:

SELECT a.*
FROM YourTable a
LEFT OUTER JOIN YourTable b
    ON a.id = b.id AND a.rev < b.rev
WHERE b.id IS NULL;

Conclusion

Both approaches bring the exact same result.

If you have two rows with max-value-in-group for group-identifier, both rows will be in the result in both approaches.

Both approaches are SQL ANSI compatible, thus, will work with your favorite RDBMS, regardless of its "flavor".

Both approaches are also performance friendly, however your mileage may vary (RDBMS, DB Structure, Indexes, etc.). So when you pick one approach over the other, benchmark. And make sure you pick the one which make most of sense to you.

Get records with max value for each group of grouped SQL results

There's a super-simple way to do this in mysql:

select * 
from (select * from mytable order by `Group`, age desc, Person) x
group by `Group`

This works because in mysql you're allowed to not aggregate non-group-by columns, in which case mysql just returns the first row. The solution is to first order the data such that for each group the row you want is first, then group by the columns you want the value for.

You avoid complicated subqueries that try to find the max() etc, and also the problems of returning multiple rows when there are more than one with the same maximum value (as the other answers would do)

Note: This is a mysql-only solution. All other databases I know will throw an SQL syntax error with the message "non aggregated columns are not listed in the group by clause" or similar. Because this solution uses undocumented behavior, the more cautious may want to include a test to assert that it remains working should a future version of MySQL change this behavior.

Version 5.7 update:

Since version 5.7, the sql-mode setting includes ONLY_FULL_GROUP_BY by default, so to make this work you must not have this option (edit the option file for the server to remove this setting).

How can I SELECT rows with MAX(Column value), PARTITION by another column in MYSQL?

You are so close! All you need to do is select BOTH the home and its max date time, then join back to the topten table on BOTH fields:

SELECT tt.*
FROM topten tt
INNER JOIN
    (SELECT home, MAX(datetime) AS MaxDateTime
    FROM topten
    GROUP BY home) groupedtt 
ON tt.home = groupedtt.home 
AND tt.datetime = groupedtt.MaxDateTime

How to get MAX() value and Record Primary Key where the value occurs in a Database?

So I found this solution. This would give the Primary Key or the record ID. It also allows for the possibility that there is more than one record with the MAX() or MIN() value.

SELECT ID, Name, Hours AS [Max] FROM Professions
    WHERE Hours = (SELECT MAX(Hours) FROM Professions)
    ORDER BY ID ASC

Here is proof using another database, though the same concept applies.

I actually wrote this code while working on a completely different problem.

how to get a Row with Max value of a column?

You can use a correlated subquery:

select t.*
from mytable t
where t.srno = (select max(srno) from mytable t1 where t1.p_id = t.p_id)

With an index on (p_id, srno), this should be an efficient solution.

Anoter common solution is to use row_number():

select pid, name, srno, rate
from (
    select t.*, row_number() over(partition by p_id order by srno desc) rn
    from mytable t
) t
where rn = 1

How to get all records having maximum value in a SQL Server table

In SQL Server, you can use top (1) with ties:

select top (1) with ties birdType, count(1) AS birdCount
from migratorybirds
group by birdType
order by count(1) desc;

Find records with MAX value in each

Check this updated Fiddle of yours: http://sqlfiddle.com/#!2/0ca23/4

SELECT temp.*
FROM temp
JOIN 
   (SELECT `Country`, `City`, `Resource`, MAX(`Volume`) AS MaxVol
   FROM `temp`
   GROUP BY `Country`, `City`, `Resource`) t
   ON temp.country = t.country 
   AND temp.city = t.city 
   AND temp.resource = t.resource 
   AND temp.volume = t.MaxVol

This query is basically making a INNER JOIN of your main table with the subquery which gets the max(volume) records for each country, city, and resource. The subquery results are aliased as table t.

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